Updating iMac (Late 2015) to use Goodnotes 6 on it?

Hi together, I am new to apples computer universe and have absolutely no clue.

I‘ve got the old iMac from my mother in law. It came with MacOs X El capitan. I need it to study, use it together with my iPad Pro and especially I need Goodnotes 6 to run on it. Apple store says Goodnotes 6 needs MacOs 14.

Is there any possibility to run this on my old iMac without crashing the pc?