How to delete a Git repository in Azure DevOps?

Is this your only repository? If so, then Azure DevOps won't let you delete it. Create another repo, and it will then let you delete this one. Permissions could also be an issue. Azure DevOps

1st you need to create an empty repo then you can able to delete it..

Select Repos, Files. From the repo drop-down, select Manage repositories. Select the name of the repository from the Repositories list, choose the ... menu, and then choose Delete repository. Confirm the deletion of the repository by typing the repo's name and selecting Delete.