Synapse EHR can send email either using its own inbuilt mail transport agent (MTA), or by using an external mail provider including gmail, outlook.com, and your own ISP. In addition it has been tested against Amazon's SES (Simple Email Service) though you will need an activated account for this.
Dedicated Account
In general it is preferable to setup a dedicated email account for patient email. This makes it more likely that you won't get patient email mixed up with personal email, and will also make it easier to import patient email sent to you into Synapse EHR. You will also then have a complete record of email sent and received.
Why use Gmail or Outlook.com ?
Generally when sending email by SMTP, your ISP (internet service provider) will generally prohibit you from sending email from your account unless you are also using their network at the same time as you send the email. So, say you're not at the office but at home using your laptop, and the ISPs for the office and home are different. Then it is likely you won't be able to send using the settings for the office. The reason that ISPs do this is to prevent relaying email or spam.
For this reason it is better to use a third party provider of SMTP services such as Gmail or Outlook.
Secure Email
In these days it is preferable to use the highest security available to send your email. For this reason you need to find the settings for your provider that allow the sending of email using encrypted transport or SSL. This doesn't mean that the email message itself is encrypted, but that no one can peek at the message while it is being transmitted. Synapse EHR defaults to using SSL on port 465.
Ideally the message should be encrypted as well, eg. using OpenPGP, but until clients that implement OpenPGP are widely and easily available, we won't be doing this.
Settings
Settings are found at Settings/User/Email and example settings are shown in the figure:
The Test Email Settings button allows you to confirm that all is working correctly.
See also this article on how to setup Google's portable SMTP server to make sure that your sent email is also stored.