Steps:
Open Microsoft Store:
Press Windows Key + S and type Microsoft Store.
Open the app and check for updates by clicking on three dots (more options) > Downloads and updates > Get updates.
Try Reinstalling Paint:
If the update didn't work, go to Settings > Apps > Apps & features.
Scroll down and find Microsoft Paint > Uninstall.
After uninstalling, go back to Microsoft Store and search for Microsoft Paint to reinstall.
Reset Microsoft Store:
Press Windows Key + R, type wsreset.exe, and press Enter. This will reset the Microsoft Store cache.