Do you have Business Manager set up? You’ll be able to give them employee permissions on Facebook for this. However, you do need to share the Instagram password for a majority of the work that is done on Instagram, including posting stories, carousel posts, IGTV posts, branded content approvals, etc.

In my experience, we change passwords monthly and once a new agency or new client transitions, we change the password again so it locks anyone else out. You can also look at what devices are logged into your Instagram account at any time!