Update textbox based on combobox selection in MVVM

Hi,

I have a View with combobox and some textboxes, which is responsible to add new Customer record.  When the View is displayed, the combobox displays of existing customers.  If user selects one from combobox I want the values displayed to textboxes. User can choose to enter data manually without using combobox.

My question is how can I update textboxes based on combobox selection in MVVM?  I can do this in Form's by manually updating the textboxes but in MVVM.

I am not asking for the detailed solution, but the general solution would be much appreciated, like do I need to update relevant Properties in ViewModel? If so what is the best approach?

Thanks