Step 1:

Go to Admin: Customers > Customer Groups. Select customer group and set “Approve New Customers” to “YES“

Step 2

Go to Admin: Extensions > Productivity Apps > Email Templates Designer. Create a new template.

Use the short-code {activation_link} .This short-code creates a link with an unique code and is sent to the registered email address. The account will be activated when the customer clicks on this link.

Step 3

Map this email template in the Admin: Extensions > Productivity Apps > Email Templates : User Templates Mapping