FAQ: How to Transfer a Client’s portal to Them after Creating It On the Backend
When you're ready to transition an account to the client you will log into their account, go to Profile, and then "Change Email" to their personal email address.
After you do that you can send them an email with the signin link to your client portal (eg: http://app.YOURCOMPANYNAME.ca/signin) and an instruction to reset their password using the "Forgot Password" option.
This will allow them to reset their password to something they choose.