My kitchen bench top has these marks (see the picture) after putting a teapot on it for a few seconds.
Thank you in advance :)
As already stated... sanding is the answer. Start with a course grit (small number, like 60) sand until the marks are gone. It's much easier if you can borrow or rent a "random orbit sander", many can be hooked up to a vacuum to control dust.
Sand the entire area... ideally the entire countertop, so you don't create low spots. Then work your way up (higher number grit) maybe 110, then 240 then 300 or so. At that point you ought to be able to seal it with some kind of penetrating oil... mineral oil even works fine. Look for "food safe" finishes at your local store.
Removing Burn marks on kitchen bench top can tricky. Whether they are caused from a hot pan or a curling iron, the likelihood of removal all depends on the severity. There are several methods for removing light scorch marks, all using items that are readily available such as toothpaste or baking soda! If the scorch goes so deep that it penetrates the kitchen bench top material (rather than just discoloring the surface), it may be necessary to replace the kitchen bench top or find a clever way to cover it up.