You need the right S Pen for your Z Fold 4.
Which S Pens work with the Samsung Galaxy Z Fold 4?
Galaxy Z Fold4 Standing Cover with S Pen Graygreen Mobile Accessories - EF-OF93PCJEGUS
Samsung Galaxy Z Fold4 to skip S Pen slot - news
Galaxy Z Fold 4 Pen Replacement + 2 Pen Tips For Samsung Galaxy Z Fold 4 S Pen Touch Stylus S Pen +replacement Tips/nibs(green)
Samsung Galaxy Z Fold 4 may not come with built-in S Pen - Android Community
Samsung Galaxy Z Fold 4 might not come with an S Pen slot - Phandroid
Does the Samsung Galaxy Z Fold 4 come with an S Pen?
Does the Samsung Galaxy Z Fold 4 support the S Pen?
Samsung Galaxy Z Fold 4 tipped to get a built-in stylus like the S22 Ultra
Does the Samsung Galaxy Z Fold 4 come with an S Pen?
How to use S Pen Pro on my Galaxy Z Fold4
Generic Original Samsung Z Fold4 5G Silicone Standing Cover With S Pen Case For Galaxy Z Fold 4 Phone Cases, EF-OF93P
Samsung Leather Book Case With S-Pen Black Samsung Galaxy Z Fold 4 + Samsung USB-C Fast Charger 25W Black