You can use the Repeating Invoice function in Xero, you can create a repeating invoice template for invoices and send it out regularly. After setting up the repeating invoice, the invoice will be generated automatically and saved as draft or approved invoice. Please click the following link for more detail and follow the steps to create a repeating invoice template.

https://central.xero.com/s/article/Add-or-edit-a-repeating-invoice-template-US-GL https://central.xero.com/s/article/How-invoice-reminders-work