By default, organization members have write access to their organization's project boards unless organization owners or project board admins set different permissions for specific project boards.
Setting a baseline permission level for all organization members
Tip: You can give an organization member higher permissions to project board. For more information, see "Project board permissions for an organization."
- In the top right corner of GitHub Enterprise Server, click your profile photo, then click Your profile.

 - On the left side of your profile page, under "Organizations", click the icon for your organization.

 - Under your organization name, click  Projects.

 - In the projects list, click the name of the project board.

 - On the top-right side of the project board, click Menu.
 - Click , then click Settings.

 - Under "Organization member permission", choose a baseline permission level for all organization members: Read, Write, Admin, or None.

 - Click Save.