Open the phone’s Settings app
Tap Accounts or Passwords & Accounts
Select the email account you want to remove
Tap Remove Account or Delete Account
Confirm the removal
If it is a Gmail account, go to Settings > Google > Manage your Google Account > Data & privacy > Delete your Google Account or remove it from the device
If it is an iPhone, go to Settings > Mail > Accounts > select the account > Delete Account
If it is an Android phone, go to Settings > Accounts > select the email account > Remove account
If the email app is separate, open the app > Settings > account > Remove account
Restart the phone after removing the account
If needed, sign out of the email app and clear the app data or cache