To view a customer details, you can go to customers page by clicking 'Customers' section in the left menu. It will take you to the customers list page. Here can you find the right customer and choose to view it from action buttons section at the right. By doing so, you will be taken to a View Customer Screen showing all the details for that particular customer.
On this screen, we have three sections, Account, Report and History.
Account section shows customers details as well as payments and invoicing history.
Report section shows a quick snapshot of the business done with the customer.
History section shows list of all the activities recorded in the system related to the customer being viewed.
You can click the 'More' button appearing at the right and it will let you edit customer or create an Invoice for that customer directly.