If the email account that you wish to use is not listed, you will need to add the email account to the iPad:
Settings > Passwords & Accounts > Add Account
If the an email account is listed, but inactive - then you will find configuration “switches” for the account; just “tap” the entry that corresponds with the account to see the configuration items for that account.
Remember, the email address that identifies your AppleID account is not necessarily provided by Apple. As such, you will need to use the email account credentials provided by your email provider.
If, however, your AppleID uses an “iCloud” email address, then yes - you will have a “switch” to enable the email account:
Settings > [Your Name / AppleID] > iCloud > Mail - set to ON