Scenario
Transaction email can be sent to customers through Invoice records only.
Solution
1. Update Customer Record
- Navigate to Lists > Relationships > Customers
- Edit any customer
- In the Preferences tab, uncheck Email next to Send Transactions Via
- Click Save
2. Update Custom Form
- Navigate to Customization > Forms > Transaction Forms
- Edit your preferred Invoice Form
- Go to Screen Fields tab> Communication:Messages tab
- In the To be E-mailed, mark the Default checkbox
- Click Save