This is kind of straight forward so bear (lol) with me, as I cannot paste pictures, so please follow the Actions and steps I say in order.
Note: When anyone submits a Microsoft Form it is automatically stored inside an Excel file HOWEVER, do NOT NOT NOT attempt to use this for anything, as due to caching issues you will only pull your hair out.
Create a SharePoint List, or if you want it to be in Excel that is fine, just please, i cannot warn you enough NOT to rely on the one that Forms creates and stores the info in. You would have to create another excel in OneDrive or SharePoint and write the data (yes duplicated essentially) but it would be available asap not hair pulling on its own time.
But I recommend creating a simple Microsoft List to store all the responses AND to store the "tracking" of creating a voucher and sending it in email successfully, the voucher ID/number whatever AND another field that would be "has been redeemed"
That makes all your tracking needs met
1. Create a Power Automate flow using a Trigger for When a Response is Submitted
2. Use the Get Response Details Action <== creates the Dynamic Properties for later use in the Flow
3. The Next Step would be a Case/Switch Action
This will allow you, to setup an Action where in the Input IS the Choice the employee selected ANDS then you would end up with 1-Many Paths. So for instance one path is "Just Mad" and another is "No I mean Really Mad" for instance and in each one you would have whatever you are going to do to create a Voucher
Now there is no way for me to explain to you have to create a Voucher, thats your own business process, however, you would put the code in those paths, to generate it.
4. Use a Create Item (for SharePoint) to enter everything you did so far including the voucher ID etc
5. Put in a Send Email V2 action
in the To, just add the Dynamic Answer that your employee put in for the email
Put in the body including the voucher
6. Put an Update Item statement for SharePoint, to update the Previously created to update the column that tracks that you sent it
Next...
However they use the voucher, that incoming system must be able to update the SharePoint item you created before by using a POwer Automate Flow to Update the previously created record to show the Voucher is now used.
That same system has to be able to use a flow or api call to SharePoint to verify if the voucher is already used or not and deny them.
That explains everything you need to do, how you integrate that with your incoming usage of the voucher is up to you to figure out.
P.S. This could also be built using CoPilot and its pretty much the same.... in your case (to a degree) but I don't want to make assumptions on licensing