Manage Wiki permissions
Azure DevOps Services | Azure DevOps Server 2020 | Azure DevOps Server 2019 | TFS 2018 - TFS 2017
By default, all members of the Contributors group can edit Wiki pages.
Manage wiki permissions
By default, all project contributors have read and edit access of the wiki repository. You can grant or restrict access to who can read and edit wiki pages by managing the wiki repository permissions.
Note
Feature availability: The built-in wiki is available with TFS 2018 and later versions.
To open the Security dialog, choose More > Wiki Security.
For definitions of each repository permission, see Git repository permissions.

Don't have access to create a page?
If you don't have access to create a wiki page, you need to contact an administrator to grant you adequate permission on the underlying Git repository of the wiki.
Stakeholder wiki access
Users with Stakeholder access in a private project can read wiki pages and view revisions, however they can't do any edit operations. For example, stakeholders aren't able to create, edit, reorder, or revert changes to pages. These permissions can't be changed. They have full access to Wikis in public projects.

FAQ
Q: Is it possible to grant permissions on a per-page basis?
A: No, permissions to access the wiki are made for all pages and not individual pages.