iPhone 13 Pro Max
iOS 17.1.2
(Phone) TurboTax v10.2
Using same login information between platforms
Mac with Big Sur 11.7.10 (can't upgrade due to legacy app use/hardware compatibility issues)
Chrome for Mac v120.0.6099.129
????? Desktop software?? The full download and install on your computer?
I thought the "mobile" app you use on an iPhone would only link with the "Online" browser-based software. Certainly, you can log into an Online account with your desktop browser to see what's been entered in a phone app.....but Don't think it links with the fully separate "Desktop" software.
Sounds like you are using the Online version on your Mac since it's too old to install the Desktop program. Maybe you're not logging into the same account on both.
How to use the Mobile App
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-use-the-mobile-app/00/26828
yes, in general, the desktop program in the online program do not share information. And the iOS app for iPhone or iPad is only a portal to the online version, so the iOS app does not share information with the desktop installed program.
however, in this case, it seems likely that the taxpayer has not actually installed the desktop program, and they are using chrome to access the website. In that case, @VolvoGirl may be correct that the taxpayer is inadvertently logging into two different online accounts.