Hello @Gourmet1 thanks for your post. There are several ways to go about this, the first one you talk about with your Square Register. To try to make it easier for someone when checking out, you can "add a customer" to the sale. Ask them if they want to receive emails, then click to Add Customer. Doing this should bring up fields on the Customer Facing Display where the customer can input their own email address. Is this what you're talking about? I think you could also choose which form fields are displayed, to make it easier for the customer, possibly eliminating the address etc. that you may not need. (Although I'd recommend capturing as much data as possible just in case for future marketing.)
You could also create a small biz card that you could hand the customer to write down their email. You or an employee could later add that into your mailing list. You could offer to add the card to a weekly/monthly raffle drawing as an incentive.
Other online options would be to create just a signup form on your Square website and give out that URL. This would then connect to your current customer database. Other options would be creating a form through Mailchimp, or Jotform, but this would also be less integrated into the Square platform.
https://squareup.com/help/us/en/article/5976-get-started-with-email-collection-tools
I hope these suggestions might help you! Happy Selling with Square!
