Hello M Usman Siddiqui,
Unfortunately, Azure Repos does not allow you to delete a pull request entirely. However, you can follow these steps to remove the sensitive information and make the PR inaccessible
Option 1- Find the PR and click Abandon and close the PR without merging.
Find the branch related to the PR and delete it. Delete the branch (removes history from the repo).
Option2- If the PR is open, rebase and force push
Checkout-