Re: How to change "link to the item" to Sharepoint link
Hi @Daniela191992,
You want a link to navigate you to the file on the Documents library page so that you could edit other metadata value?
If so, I am afraid that there is no OOTB way to add a comment to a file on documents, we suppors it for List items not for file on ducuments library.
What's more, the comments for file on Documents blibrary is always marked as check in or check out, not sure if it is what you want to view.
UPDATE:
I want to explain to you that we could create a link to a file to naviaget you to the version history page, however you could only add a comment to this file when you check in.
Here is the URL you need to configure within the Create an approval:
https://SiteURL/_layouts/15/Versions.aspx?list=GUID&ID=ID
Note that the GUID could be captured as below:

After that, we could achieve as below:
