Populate field from url

Is there a way to populate a field with a number/text from the url?

Example:
My page www.site.com/form has a review form on it. But I want to populate a field with a order number.

Q1: How, if possible, should the URL look like so that GF can fetch the order number?
Q2: How can I polulate the field with that number?

Please refer to the method here:

I have read the documentation, and i know how to populate fields through URL parameter, but i’d like to know if these parameters need to be sanitized or not … is it safe to use variables in GF without sanitization?

ie.
I have 3 button on my page, every button is linked to a form a the bottom of the page.
So i need to pass a parameter adding a variable to the link
page/?product=fish
or
page/?product=drink

And the form pre-populate the product field with parameters submitted by the URL

The values are sanitized by Gravity Forms.