If you want it to last a while, consider using oil based paint. I painted my bathroom countertop with shellac based primer, latex paint and top coated with polycrylic. It lasted about a year before we replaced it with a wood countertop.
Clean it well before painting for best results.
Brenda, here is a good idea to help: https://www.hometalk.com/13563405/painting-over-dated-formica
I found the paint tends to chip. I did find great contact paper that makes it look real and made just for counter tops.
I painted my laminate kitchen counters in faux granite and it lasted perfectly for YEARS. First, clean well and use a deglosser. I also did some light sanding so the paint would grip.
I had already purchased an oil based "direct-to-metal" paint from Sherwin Williams to paint my shed. I used that paint as the base coat for my faux granite. I HIGHLY recommend you do the same as I believe that base paint and the layers of poly were what made this project impervious to damage (of course use cutting boards, etc. as this isn't really granite).
Use any colors paint you like in your granite (use real granite as a guide). I used all latex paints. Apply with a natural sea sponge by dabbing each color randomly all over the counter. Build up colors by layers paints. Periodically step back to see if you need any adjustments.
I then sealed it all with probably 5-6 coats of poly, letting each coat dry a couple of days before recoating.
As said, this lasted in perfect condition for years. In fact, when I sold the house I had to make sure potential buyers knew it was not really granite - that's how well it turned out!
Super easy project to do. It only takes maybe 1/2 hour for each layer you add on and that time gets shorter as your layers build up. Have fun and go for it!