Thanks for posting again here. Allow me to share some details about resending the email invitation to your employee.
When adding a new user to your account, you'll see the Resend invite button if they haven't accepted the invitation yet. Check this screenshot as reference:
Since you've mentioned that this option isn't on the drop-down, it could be due to a browser error. You'll want to use an incognito window and resend it from there.
Google Chrome: Ctrl + Shift + N
Safari 11 or newer: ⌘ + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Microsoft Edge: Ctrl + Shift + P
Also, it could be that accumulated temporary internet files in the browser are the root cause of this unusual behavior. I suggest you clear the cache and make sure you're using a supported and updated browser.
I've added more links for your guide on how to manage users: