You can email directly form Evopos in many parts of the program.
The Email settings are set in Settings / System / Comms.
Any Contact can have 'Default Document' set to Email so that the Invoices Statements etc are automatically emailed
Any Contact can also have 'Default Reminder' set to Email so any reminders are automatically emailed
You can email directly from the Contacts screen by selecting the 'People' tab clicking the 'Email' button next to the email
You can email any report by selecting the Email option on the report viewer
The Comms section in Contacts allows you to bulk email selected customers for a wide range of criteria.
See Notifications for general information on sending email and SMS notifications