Hi Madhura,
Just make an association between claim request and Approver and at the time of approving store the approver in that association.
Then when showing the request retrieve that association too.
If I'm not wrong, I hope it helps.
Hi, just to complement to Bhargav's answer:
Please check the Mendix documentation to learn more about associations:
https://docs.mendix.com/refguide/associations/
I hope that information is helpful to you. Go make it!