Constant Contact

You can import an exported customer email CSV file from TransActPOS into Constant Contact.
 
Go to www.constantcontact.com, and click on the Contacts tab.
 
Click on the Add Contacts dropdown, and select Import from other apps.
 
On the Upload From File screen, drag and drop or browse for the exported CSV file.
 
Match the field names to the CSV import file for First Name, Last Name, Company, and Email Address.
Create a new custom field for Customer ID.  Click Continue to complete the import.