Hi @WittigLD - Thanks for reaching out to us here on the Square Seller Community👋
When creating a new Invoice, be sure to check the box that says, "Allow customer to add a tip" in the Payment Options section. I added an image below so you can see what this will look like on the New Invoice page.
If your customers are still not seeing this option after you've enabled the setting, please reach out directly to our Support Team for further assistance. They will be able to take a look at your account and Invoices to double-check your settings. They are also able to report this issue to our Engineers for further investigation if needed.
I hope this information is helpful but please do let us know if you have any additional questions. Always happy to help! 😊
