In GitHub we have services that integrate with GitHub which can help you do anything from enabling continuous integration to closing stale issues and pull requests. A GitHub App acts on its own behalf, taking actions via the API directly using its own identity, which means you don’t need to maintain a bot or service account as a separate user.  

GitHub Apps can be installed directly on organizations and user accounts and granted access to specific repositories. They come with built-in webhooks and narrow, specific permissions. When you set up your GitHub App, you can select the repositories you want it to access.  

User can connect GitHub identity to third-party applications using OAuth. When authorizing one of these applications, you should ensure you trust the application, review who it's developed by, and review the kinds of information the application wants to access. 

Marketplace 

In marketplace you can find hundreds of applications which you can easily integrate with GitHub and start using after giving access to organizations or repositories. 

Review Order 

After you select the application, you will get a billing plan information with the service that application is going to provide. 

Authorize Application 

Now Install and authorize application and also check the types of permissions application are requesting. 

When you want to use a application that integrates with GitHub, that application lets you know what type of access to your data will be required. If you grant access to the application, then the application will be able to perform actions on your behalf, such as reading or modifying data. 

Types of application access and data 

Applications can have read or write access to your GitHub data. 

• Read access only allows an application to look at your data. 

• Write access allows an application to change your data. 

As an owner of an organization, you may receive requests from members of your org to install GitHub or OAuth apps. When reviewing these installation requests, pay close attention to the permissions they are requesting. Like this GitHub user can start using applications from marketplace. 

Requesting updated permissions 

Applications can request new access privileges. When asking for updated permissions, the application will notify you of the differences.