Advocacy is an activity by an individual or group that aims to influence decisions within political, economic, and social institutions. Advocacy includes activities and publications to influence public policy, laws and budgets by using facts, their relationships, the media, and messaging to educate government officials and the public. Advocacy can include many activities that a person or organization undertakes, including media campaigns, public speaking, commissioning and publishing research. Lobbying (often by lobby groups) is a form of advocacy where a direct approach is made to legislators on a specific issue or specific piece of legislation. Research[whose?] has started to address how advocacy groups in the United States and Canada are using social media to facilitate civic engagement and collective action.
There are several forms of advocacy, each representing a different approach in a way to initiate changes in the society. One of the most popular forms is social justice advocacy. Cohen, de la Vega, and Watson (2001) state that this definition does not encompass the notions of power relations, people's participation, and a vision of a just society as promoted by social justice advocates. For them, advocacy represents the series of actions taken and issues highlighted to change the “what is” into a “what should be”, considering that this “what should be” is a more decent and a more just society  Those actions, which vary with the political, economic and social environment in which they are conducted, have several points in common. For instance, they:
Question the way policy is administered
Participate in the agenda-setting as they raise significant issues
Target political systems "because those systems are not responding to people's needs"
Are inclusive and engaging
Propose policy solutions
Open up space for public argumentation
Other forms of advocacy include:
Budget advocacy: another aspect of advocacy that ensures proactive engagement of Civil Society Organizations with the government budget to make the government more accountable to the people and promote transparency. Budget advocacy also enables citizens and social action groups to compel the government to be more alert to the needs and aspirations of people in general and the deprived sections of the community.
Bureaucratic advocacy: people considered "experts" have more chance to succeed at presenting their issues to decision-makers. They use bureaucratic advocacy to influence the agenda, although at a slower pace.
Express versus issue advocacy: These two types of advocacy when grouped together usually refers to a debate in the United States whether a group is expressly making their desire known that voters should cast ballots in a particular way, or whether a group has a long-term issue that isn't campaign and election season specific.
Health advocacy: supports and promotes patients' health care rights as well as enhance community health and policy initiatives that focus on the availability, safety and quality of care.
Ideological advocacy: in this approach, groups fight, sometimes during protests, to advance their ideas in the decision-making circles.
Interest-group advocacy: lobbying is the main tool used by interest groups doing mass advocacy. It is a form of action that does not always succeed at influencing political decision-makers as it requires resources and organization to be effective.
Legislative advocacy: the "reliance on the state or federal legislative process" as part of a strategy to create change.
Mass advocacy: any type of action taken by large groups (petitions, demonstrations, etc.)
Media advocacy: "the strategic use of the mass media as a resource to advance a social or public policy initiative" (Jernigan and Wright, 1996). In Canada, for example, the Manitoba Public Insurance campaigns illustrate how media advocacy was used to fight alcohol and tobacco-related health issues. We can also consider the role of health advocacy and the media in “the enactment of municipal smoking bylaws in Canada between 1970 and 1995.” 
Special education advocacy: advocacy with a "specific focus on the educational rights of students with disabilities."
Different contexts in which advocacy is used:
In a legal/law context: An "advocate" is the title of a specific person who is authorized/appointed in some way to speak on behalf of a person in a legal process.
In a political context: An "advocacy group" is an organized collection of people who seek to influence political decisions and policy, without seeking election to public office.
In a social care context: Both terms (and more specific ones such as "independent advocacy") are used in the UK in the context of a network of interconnected organisations and projects which seek to benefit people who are in difficulty (primarily in the context of disability and mental health).
In the context of inclusion: Citizen Advocacy organisations (or programmes) seek to cause benefit by reconnecting people who have become isolated. Their practice was defined in two key documents: CAPE, and Learning from Citizen Advocacy Programs.
Groups involved in advocacy work have been using the Internet to accomplish organizational goals. It has been argued that the Internet helps to increase the speed, reach and effectiveness of advocacy-related communication as well as mobilization efforts, suggesting that social media are beneficial to the advocacy community.
People advocate for a large number and variety of topics. Some of these are clear-cut social issues that are universally agreed to be problematic and worth solving, such as human trafficking. Others—such as abortion—are much more divisive and inspire strongly-held opinions on both sides. There may never be a consensus on this latter type of issues, but intense advocacy is likely to remain. In the United States, any issue of widespread debate and deeply-divided opinion can be referred to as a social issue. The Library of Congress has assembled an extensive list of social issues in the United States, ranging from vast ones like abortion to same-sex marriage to smaller ones like hacking and academic cheating.
Topics that appear to involve advancing a certain positive ideal are often known as causes. A particular cause may be very expansive in nature — for instance, increasing liberty or fixing a broken political system. For instance in 2008, U.S. presidential candidate Barack Obama utilized such a meaning when he said, "this was the moment when we tore down barriers that have divided us for too long; when we rallied people of all parties and ages to a common cause."Change.org and Causes are two popular websites that allow people to organize around a common cause.
Advocates and advocacy groups represent a wide range of categories and support several issues as listed on worldadvocacy.com. The Advocacy Institute, a US-based global organization, is dedicated to strengthening the capacity of political, social, and economic justice advocates to influence and change public policy.
The phenomenon of globalization draws a special attention to advocacy beyond countries’ borders. The core existence of networks such as World Advocacy or the Advocacy Institute demonstrates the increasing importance of transnational advocacy and international advocacy. Transnational advocacy networks are more likely to emerge around issues where external influence is necessary to ease the communication between internal groups and their own government. Groups of advocates willing to further their mission also tend to promote networks and to meet with their internal counterparts to exchange ideas.
Transnational advocacy is increasingly playing a role in advocacy for migrants rights, and migrant advocacy organizations have strategically called upon governments and international organizations for leverage.
Transnational advocates spend time with local interest groups in order to better understand their views and wishes.
^ abObar, J.A.; Zube, P.; Lampe, C. (2012). "Advocacy 2.0: An analysis of how advocacy groups in the United States perceive and use social media as tools for facilitating civic engagement and collective action". Journal of Information Policy. 2: 1–25. doi:10.2139/ssrn.1956352. S2CID145712218. SSRN1956352.
^Asbridge, M. (2004). "Public place restrictions on smoking in Canada: assessing the role of the state, media, science and public health advocacy". Social Science & Medicine. 58 (1): 13–24. doi:10.1016/s0277-9536(03)00154-0. PMID14572918.
^Ope, J.A.M. (1999). "From the Streets to the Internet: The Cyber-Diffusion of Contention". Annals of the American Academy of Political and Social Science. 566: 132–143. doi:10.1177/0002716299566001011.
^Eaton, M. (2010). "Manufacturing Community in an Online Activity Organization: The Rhetoric of MoveOn.org's E-mails". Information, Communication and Society. 13 (2): 174–192. doi:10.1080/13691180902890125. S2CID141971731.