I work at a startup where I have to consult freelancers for some work, now I do not wish to give the credentials of the service I am using to the freelancer. How do I curb access in a way that works for both of us?
tldr: without separate account and workspace mechanisms built-in into a service, you cannot safely give the credentials
If a service doesn't have some kind of separate account + either:
access-control list (ACL) built-in (with separate account)
separate password/token
other built-in mechanism
there's no other way than giving access and changing password afterwards (and ensuring they cannot change email).
partial solution could be written agreement/NDA (I'm not into legal, so cannot tell what exactly do you need here)