You will be able to send the new prescribed information to current tenants on 1st May using a built-in RPost account (see https://rpost.com/ ) The cost will be less than 50p per send (+VAT) and will be added to your Rentman bill.
You don’t need to create your own account with RPost for this one-off but you may wish to after 1st May so as to have proof of all emails sent.
Re-iterating a previous post… legal advice from TfP recommends NOT sending until 1st May (the legal requirement is to send by 31st May)
Nigel's Rentman blog 
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