Can I use this in my glowforge

We are not familiar with a glowforge, so we are unable to  answer this question.

How do I go about getting a sample of this product. Is it fine glitter or not? Smooth or rough? Also, is it printable?

We offer Samples through our Sample Request form.  This is not printable.  The Mirri Sparkle Glitter card stock will accept laser or digital printing.

Can you tell me if the back of this cardstock has a paper-like finish or if it’s a slick glossy finish?

The white back side is a matte white finish.  It is not a glossy finish.

Hello, Does the glitter paper come in any of the colors below? Thank you so much!! 1.) white 2.) cream 3.) turquoise 4.) Tiffany blue

You can see all colors of glitter card stocks here https://www.cutcardstock.com/collections/glitter-card-stock