If you have a Stripe account and have linked it to your profile, you are able to create an invoice for a customer and then send it to the customer via email along with a note requesting payment. In that email, the customer will be given a link that they can click to access your payment page.
If you click on an invoice that you've created, the payment request can be executed via the following button.
If you're unable to see this button below the invoice, there are 2 items to check.
1) Ensure that you have added your Stripe keys to your profile.
In order to do this, within the side menu, navigate to Invoicing Invoicing Setup Stripe Keys page. Within this page, please add all 4 keys that are requested.
2) Ensure that your website is live.
If you are on the Free Plan, ensure that a subdomain has been filled in without the Site Content and Address page.
Alternatively, if you have just started a paid subscription, please allow 48 hours for your desired domain (eg. superclean.com), which you would have indicated on the Site Content and Address page of the website setup process, to become active.