Generally speaking, HMRC will communicate with you by sending a letter or calling you. It will never ask for personal details by email. Accordingly, you can disregard any emails you receive from HMRC that do ask for personal information, particularly bank details, as they will likely be scams...
However, HMRC is starting to send out more information by email. In particular:
Employer Bulletin 56 - email
HMRC sends informational emails several times a year to employers who have registered to receive them. These emails never ask you to provide personal or financial information.
The latest batch of emails issued by HMRC was sent 14 October 2015. The emails are titled ‘Important information for employers’ and refer to Employer Bulletin 56. The emails include links which direct recipients to pages on the HMRC website, including advice about online security.
PAYE notices and reminders
If you’ve set up email reminders and notifications using one of the options available in HMRC’s PAYE Online Service you’ll automatically get sent an email when there’s something new for you to view.
HMRC has also started to send electronic reminders if you don’t send your payroll submissions on time, or you’re late making payments to HMRC.
You may also receive email warning notices if HMRC hold records for you, and where you have yet to submit any PAYE reports to HMRC in real time. These messages will inform the employer that they need to act now to avoid incurring penalties, and they should either advise HMRC if they no longer employ anyone, or start reporting in real time.
VAT Returns - email reminders
HMRC will send an email to customers to remind them when their VAT return is due if they have registered to receive email reminders. The emails are entitled ‘Reminder to file your VAT Return’ and contain links to a further information page and a link to the sign in page on GOV.UK. These emails will never ask you to provide personal or financial information.
VAT Registration - email
HMRC will send an email to customers who have registered for VAT using HMRC online services. HMRC will use the email address customers have provided to advise that they need to log into their online tax account in order to view a message in the secure messaging area. These emails will never ask you to provide personal or financial information.