Hi @Harshardhan-11,
You can modify the upload.aspx located in the path:
C:\Program Files\Common Files\microsoft shared\Web Server Extensions\16\TEMPLATE\LAYOUTS\uploadex.aspx
The upload form url will be like:
You can check the list guid using JavaScript to make sure it only apply for one library:
Add code under PlaceHolderMain tag:
The list guid can be found in SharePoint Designer:
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