See Gmail instructions here
Include the sample signature text below in all emails from your clinic:
Dear Patient!
From now, please contact us using the patient portal at Certific
This is the quickest and safest way to communicate your health problem or request. You can send a request 24 hours a day, but please note, we will only reply during the centre's opening hours.
Emails are not monitored regularly and may take over 7 days to receive a reply.
Please contact our customer support team here, should you need any further assistance.