HMRC do not send communications to tax payers by email. If you receive an email purporting to be from HMRC, it will be some sort of “scam” and should be ignored (deleted from your PC).
Do not under any circumstances open any attached files or disclose any personal information. Typically, the email will offer you a tax refund if you send your bank details, or some other inducement to part with similar information.
HMRC will either call you or send a letter if they need to communicate with you.