The S Pen is an optional add-on for the Galaxy S21 Ultra. But the move will fuel speculation the firm will phase out its separate Note handset range.
Samsung told the BBC it had yet to make a decision about this.
The company's handset sales have declined more quickly than the wider market. One expert said a streamlined line-up might help address this.
"There's increasing logic for Samsung to converge the Galaxy S and Note platforms, because there's so little differentiation between the two kinds of devices now," said Ben Wood, from the CCS Insight consultancy.
