If you have a connected email service, you can send a preview of the email while creating or editing an email template.
The preview email address will default to the current user's email address. You can update this to any other address, but multiple addresses cannot be entered. Click “Send Preview” when ready to send.

Contact and Company merge tags will be replaced with example text. Invalid or placeholder merge tags will not be replaced and will show up as the raw merge tag when the email is sent.