First of all, create a segment and add the users to whom you want to send coupon codes. Make sure that users have email permission enabled.
Now create a recurring campaign as shown in the figure below.
Give a unique name to the campaign and add a recurring period to it.
Save these details and hit the next button.
Next, specify the target audience by selecting the segment you just created.
Add the Shopify coupon node to the campaign canvas and specify the coupon code as shown in the figure below.
Enter coupon id, select coupon type as general or unique, and hit the Ok button.
Now add the Email node to the campaign and specify the email code as “{%=$Current.coupon_code%}”
Add wait to campaign and then publish the campaign.
Users will receive the emails containing the coupon codes as shown below.