To change the font size in Sticky Notes on Windows 11, follow these steps: 1. Open the Sticky Notes app. 2. Click on the three dots (settings) in the top right corner of the note. 3. Choose 'Note settings.' 4. Under the 'Font size' section, use the slider to adjust the font size. 5. Close the settings menu. The font size in your Sticky Notes will now be updated.