I want to engage a vendor for developments on our SF site. Unfortunately, I'm somewhat of a newbie to SF and am thrown into the deep end of managing a vendor, while we don't have SF admin (yet). I'm on the hunt for an admin, but need to get the development going.
The vendor told me they need Salesforce org credentials, which I think provides them with access to our SF instance. I assume they need access to the sandbox and production.
We have quite sensitive data on our system, so I'm a bit wary of given full access.
How do I give a vendor access to SF, so that they can develop the solution that I'm after, while not jeopardising the integrity of our system?