A customer can be added from Data > Customers or from a POS, Quote, or Work Order.  Click on the + symbol to add a new customer.

In the header of the New Customer window, select the Customer Type; Company or Person.  This will automatically add the details to the People or Companies List.

 

In the banner of the Customer window, add the Customer # and Customer Name.  

In the Details Tab, add contact information.  If adding an email address and the customer would like to receive their receipt/invoice automatically, check the "Auto Email Tender Receipt" in the banner.

If the Finance tab is available, you can add a credit limit, sales pricing levels, require a PO for orders, etc.  Note: not all tenants will have the same fields. 

Click Save when complete.