How do I set up my email on my phone or computer?

In cPanel, open Email Accounts and choose Connect Devices beside your email address. Use Secure SSL/TLS Settings (Recommended) to set up your mail app: copy the incoming and outgoing server names, use your full email address as the username and enter that mailbox's password. Choose IMAP to keep mail folders in sync across your devices.

Find your own connection settings

Sign in to your account, find the correct hosting service in Services and choose Log in to cPanel. On mobile, choose cPanel.
Open Email Accounts and find the full address you want to use. Choose Connect Devices on that row, not beside the System account.
On Set Up Mail Client, find Mail Client Manual Settings → Secure SSL/TLS Settings (Recommended). Keep that page open while setting up the app.
Copy the Incoming Server, Outgoing Server and port numbers shown there. For the secure cPanel settings, IMAP normally uses 993 and SMTP uses 465. Use your mailbox's displayed values rather than guessing a server name from your website address.

What the app needs

Username: your full email address, including the part after @. Password: the password for that mailbox. Your client-account or cPanel password will not sign in to a separately created mailbox.
IMAP: receives mail and keeps folders in sync. SMTP: sends mail. Both need authentication, meaning the app must sign in using the mailbox username and password.
Use the secure connection option, labelled SSL/TLS in many apps. Do not dismiss a certificate warning or switch off connection security to force setup through.

Add it to your app

In Outlook for iPhone or Android, open your profile icon, then the settings gear. Under Mail Accounts, choose Add Mail Account → Add Email Account and enter the address. For manual setup, choose IMAP and enter the values under Advanced Settings. See Microsoft's Outlook instructions for its current screens.
For Apple Mail, follow Apple's account setup instructions, using Other for a cPanel mailbox rather than selecting iCloud, Google or Microsoft Exchange. Use the secure settings from Connect Devices when asked for server details.
After setup, send a message to another address you control and reply to it. Check both directions. Keeping mail in sync means deleting a message on one IMAP device can also remove it from the other devices.

If setup fails

Try Check Email beside the mailbox in cPanel. If webmail opens but the app cannot connect, recheck the app's server names, full username, password and secure ports.
If you have forgotten the mailbox password, use the mailbox-password steps before updating it in your apps. Resetting the cPanel password does not reset a separately created mailbox password.
Contact Tech/Server with the app name, device, email address and exact error. Do not send passwords or an exported file containing them.