I remember being able to sync my email accounts with my iPhone in iTunes, I forget which version of OS X. It was under the Info tab when I selected the device in iTunes. I don't see that option anywhere now. Was it moved somewhere else? I don't see anything relevant in System Preferences or Mail either.
Edit: I saw this on StackExchange, but I don't want to use iCloud Keychain. Is that the only way?
Edit: I saw this on StackExchange, but I don't want to use iCloud Keychain. Is that the only way?