As with most services there is a cost involved but with Stripe there is no monthly fees, you only pay for what you use. Please see their website for pricing information.
After signing up to Stripe, you will need to add the account to your Xero subscription.
To do so navigate to Settings>General Settings>Payment Services and follow the prompts as they arise.
Once set up in Xero, when you email invoices to customers with an online link to the invoice they will be prompted with a pay now button.
In normal circumstances, to pay you a customer would have to get the old cheque book out or fire up the computer, log in to internet banking and process a payment. Through Stripe, customers simply need to click on “Pay Now” and they can pay direct with their credit cards without having to log in anywhere or go through any other steps.
Using payment services like Stripe can help to avoid late payment or sometimes no payment, from those customers that pick up a bill and leave it on the kitchen table to get lost with every other piece of mail they receive. It enables customers to view and pay a bill in one fluent motion.