The video that Vikas linked you to will show you how to use forms. You will also want to read this blog post to learn how to use the request response type trigger to intercept access requests and dynamically approve/deny them before they are sent to an approver.
Here’s how your workflow should work at a high level:
- Use the Access Request Submitted trigger to intercept an access request. The above blog will show you how to do it.
- Send a form to the user asking for their consent. The video that @vguleria links to will show you how to do that. If the user approves, then you can respond to the event trigger by approving the request. If they deny, then you can respond to the trigger by denying the request, and it won’t go to any additional approvers. The blog I shared above will show you how to respond to the trigger.