How to autofill a TextBox on a button click on other webform

I am making an asp.net website and I have a button on the main WebForm that it is hyperlinked with WebForm2.
The WebForm2 that opens is a typical contact form that contains some text boxes, drop down lists and a button that sends an e-mail with the information that I entered. But because I am making an e-commerce website, depending on which button(on which product) is clicked on the main WebForm, I need to autofill the TextBox that contains the "Product Name" on the WebForm2.

So my question is, how to make the button on the main WebForm autofill the TextBox on the WebForm2 that contains the Product Name?