From Krita Documentation
- Input Pressure Global Curve : This is the global curve setting that your tablet will use in Krita. The settings here will make your tablet feel soft or hard globally.
- For Krita 3.3 or later: Tablet Input API (on Windows 8 or above only)
- WinTab: Use the WinTab API to receive tablet pen input. This is the API being used before Krita 3.3. This option is recommended for most Wacom tablets.
- Windows 8+ Pointer Input: Use the Pointer Input messages to receive tablet pen input. This option depends on Windows Ink support from the tablet driver. This is a relatively new addition so it's still considered to be experimental, but it should work well enough for painting. You should try this if you are using an N-Trig device (e.g. recent Microsoft Surface devices) or if your tablet does not work well with WinTab.
If your tablet doesn't work with Krita, check out the page on drawing tablets.