How do I delete an email account from my iphone and iPad please?

Settings->Mail->Accounts->Account Name and tap on Delete Account.

If it was a Microsoft Exchange account, it may have a profile associated with it, you may need to delete before it will let you remove the account. Go to Settings->General->Profiles and Device Management and remove the Office Profile.

Guess I took too long to find the exact location of the Profiles setting. 😣

Go to Settings>Mail>Accounts>tap on the account you wish to remove. At the bottom of that next page, tap Delete Account. If that does not appear, it could be the company installed a profile on the phone for your corporate account. Go to Settings>General>scroll down and see if you see a heading Profiles. If you do, see if there is a profile for your company and delete that, then see if you can remove the email accounts.