Hi Christina Liang,
Thank you for reaching Microsoft Community. We're sorry for the trouble this has caused you.
I just want to clarify the concern you raised above, are you trying to scroll pages using the touchpad on the keyboard or the touch screen itself?
If this is for the touchpad I recommend to check Touchpad settings if one finger to scroll is available.
Go to Settings > Devices > Touchpad. Adjust your settings under Touchpad.
I hope to hear from you soon.
Kind regards,
Lavenia