The most common requests to have is to provide permission to something on SQL Server, either to a linked server, any server object or database object or something specific to a database. It is almost impossible to know all the required permissions possible which let the user do their task with minimum permission .
In such cases I have always been saved by MS Docs, and I think this is the least used part of the docs.
Let us say that you have to provide the permission to a user to create a credential, than which permission do you need to assign this user?
Search Credential in docs it provides this link.
In this link there is one section called permission, and this is the permission that you will need to grant someone who wants to create a credential.
In majority of tasks there is a MS doc page with a section “Permissions” that will help you out.
I hope it helps!