How can I make designs on countertops?

Depends on what kind of countertop.

This how to video might help: https://m.youtube.com/watch?v=7kVrmsP0dCg

I did mine with epoxy resin. Love it. You can make a design and color it with clear or color your epoxy resin mixture. You can find lots of ideas on Lipari. Com

I used ENVIROTEX resin. Totally ok around food and they use it on bar tops. I painted my kitchen countertops with stone spray and made it look granite like. Then poured envirotex resin on top of it. In your case instead of stone spray you can make your designs and then pour the resin on top. You might want to make a frame for the sides of the countertop because the edges are tricky to get a smooth finish. But whatever you do, cover the lower cabinets with plastic because when it gets poured, it will drip down off the sides. Follow the directions on the box and you will love the result. For a few years after we did it, people thought it was granite. Good Luck! Then you use a blow torch to get all the bubbles out. Follow the envirotex directions on the box. Google tutorials. It's a great product and our countertops have held up for years now. People ask me if it was real granite. I think we used 5-6 boxes of envirotex for our countertops. Totalling around $300. hope this helps. It definitely has extended our old pink laminate countertops for another 5-6 years before we can afford real granite or quartz. Good Luck!

This video might be helpful for you... https://www.youtube.com/watch?v=zGbV1EIwZDg