https://wccftech.com/using-regular-s-pen-with-galaxy-z-fold-3-can-damage-display/

As most of you know, the Galaxy Z Fold 3 is the first Samsung foldable smartphone to get S Pen support, but if you have a stylus lying around from your previous purchases, do not attempt to use it with this handset, and we will explain why.

Even though the Galaxy Z Fold 3 comes with a protective film that claims to tout 80 percent more durability than the previous-generation one, Samsung does not recommend using a regular S Pen on it. Instead, the company states that it has developed ‘Pro Tips’ for the S Pen Fold Edition and the S Pen Pro. The biggest difference is that the two new accessories’ tips are softer than the regular ones.