Payrexx allows to create a sales page and use backend office in 9 languages being logged into the same account . Therefore, your customer will be able to view Pages in 9 languages.
Navigate to Settings -> General settings -> enable multilingual frontend
By clicking on a deactivated language you change its status to activated.
Your customers are able to change the Page to the desired language in the right-upper corner.
If you change the language in the administration section you change it for yourself (backend).