Join my company paid zoom account

Welcome to the Zoom Community, @KatyaTurner1976.

There's a process for the Account Owner to follow to invite another user to the account.  See this Zoom Support article for details, and pass it along to your coworker:

https://support.zoom.us/hc/en-us/articles/201363183-Managing-users

Once you're on the account, another License needs to be acquired and paid for, and assigned to your user login.  But once you're both on the account, there are some features that are not available to you if you are on separate accounts.