changing text of a button

[LAazsx]

Hi, how can I automatically change the text property of a shape?

Here's the scenario,
I have a rectangle that functions as a button. When the button is clicked, the text will be transferred from a variable.

I don't know how to do this since the macros is not really a property of the object. In VB, the code is
btn1.text = variable
how do i do this in VBA?