In order to use the Email Copy functionality in the RepZio Sales app an email account must be set up in the Apple Mail app 
on the iPhone or iPad.
iOS 15 changed the email setup steps for adding email to devices
Go to:
1. Settings using the left menu options scroll down to > Mail > Accounts > Add Account
2. Under Accounts pick your email account type by name (iCloud, Google, Yahoo, Microsoft etc). If you email type is not listed, follow directions below to setup manually.
3. Tap Next / Continue. Mail will try to find the email settings and finish your account setup. If Mail finds your email settings, tap Done to complete your account setup.
Email setup for older versions of iOS prior to 11
Go to:
- Settings > Mail > Accounts > Add Account.
- If you see your email provider, tap it to add your account automatically. If you don't see your email provider, tap Other to add your account manually.
Set up an account manually
Make sure that you know your email settings. If you don’t know them, you can look them up or contact your email provider. Then follow these steps:
- Tap Add Account, tap Other, then tap Add Mail Account.
- Enter your name, email address, password, and a description for your account.
- Tap Next. Mail will try to find the email settings and finish your account setup. If Mail finds your email settings, tap Done to complete your account setup.
Referenced from Apple Support - for further support from Apple use this link
https://support.apple.com/en-us/HT201320