When I want to download the app, it wants to use my personal gmail account. If I go ahead with the download can I change that without affecting my personal account?
Once you install the iOS mobile app you can set it up manually “with any account/s you want”. They can be the same or different accounts. Up to you.
So yes you can download the app from the app store with your personal Gmail account and then setup the eM Client mobile app with a different mail account.
If you setup an IMAP, Exchange, Office 365 or iCloud account on the mobile app any message changes or message deletions etc will also reflect on the other mail clients “configured with the same account”.
Now if you want exactly the same eM Client desktop accounts, tag / labels & settings etc on the mobile iOS app, you can use the “QR Export code option” in the desktop menu". Your iOS mobile app will scan the desktop QR Code at the end to complete the same identical account/s setup.
To export via QR Code, go to “Menu / Tools / QR Export” (Pc) or “Tools / QR Export” (Mac).