How can I add my CFO as a user to review/and continue with what I've done so far on my 2020 return

TurboTax is do-it-yourself software so there is not an option to add users to your TurboTax account.   We don't recommend that you share your account access credentials with other people.   You can always print and save your documents and share them with your financial associates if you need to.   Can I print or save a copy of my TurboTax Online return before I file it?

We protect your Intuit Account with the latest technology for privacy and security. Unfortunately, this doesn’t allow a safe and secure way to merge multiple accounts.  

You have a CFO?  Are you doing a Business return?  Turbo Tax is for personal returns.  The online Self Employed version is for personal returns that report business on Schedule C.   What kind of business do you have?  Do you need to file a separate 1065 or 1120 Business return?  

If you want someone else to have access to your return you should consider using the CD/Download Desktop program installed on a computer.  It has more features and advantages over the Online versions.   We can tell you how to switch.