Ball of the hand interferes with pen input (2in1, convertible notebook)?

I recently bought a 2-1 laptop, which I got for university because of the tablet function. Now I have the problem that, for example, if I keep touching the surface with the heel of my hand while writing, blocking the actual writing with the pen.

Do you have a solution how to get around that best?

What kind of tablet do you have?
Do you use an ordinary stylus (which you can use with your mobile phone, tablet, Windows 2 in 1 convertible, etc.) or an active pen that came with the tablet? With the latter, a distinction should actually be possible, you can either make the whole thing in Windows in the input settings for input with a pen or in your respective program.