Having added your accounts to Internet Accounts in macOS, you’ll likely want to access those same accounts on your iPhone & iPad.
The setup procedure is much the same, but takes place within Settings, under Accounts->Mail.
Having followed recommended Preparations, you will have already decided where your contacts, calendars, notes, are to be stored. With this in mind, you can add your accounts on your other devices, and apply settings according to your decisions.
To add your email, or internet account on your iOS or iPadOS device, from the Home screen, tap Settings.
Existing accounts will be listed here, where you can change settings.
To add another account, tap Add Account.