To create new invoice go to Sales -> Invoices and click on the button Create new invoice
Select Customer, when selecting a Client the customer informations will be fetched directly from the customer’s profile. Another option is that you can click on the edit icon and directly add the desired customer informations, this also is applied for the billing informations they are also fetched when selecting a customer.
NOTE: If you want the billing details to be auto populated when selecting the customer you need previously to have added Billing details in the customer profile.
Billing and Shipping – If you change the billing and shipping informations after selecting a client and click on the edit icon, this will be changed for the Invoice but in the customer profile the informations will remain the same.