InputBox-ow to have a user input text in a inputbox

I need to know how to have a user input text in a inputbox and append to the end of a cell.

Example:
Cell A1 has Customer Name: (already in the cell I need to have an input box setup so when the customer runs the micro it will prompt then to enter their name. Once their name has been enter it will append to the end of A1.)
After input box: Cell A1 Customer Name: Joe Blow

I'm stuck.
Thanks ahead.

Something like

Dim res As String

res = InputBox("Enter something")
Range("A1").Value = Range("A1").Value & "" & res