The script made available here can be used to obtain html report on pull requests. You can pass the status of pull request and obtain the pull request list with details such as link to the pull request as well as approver details etc. To execute the script you can use below syntax.
.\FindPullRequests.ps1 -token 'PAT' -collectionUri 'https://dev.azure.com/OrgName'
-teamProjectName 'teamprojectname' -prStatuses @('active','completed')
You can obtain the report for more than one status by passing them or you can pass a single state such as active to obtain active pull request details.The script obtains all pull request for a given state and then evaluates its vote state to determine the review actions performed.
here is used in the script. The report would be generated as an html file in the script location.