Hey there!
Nice to meet you! I'm Randy, an Independent Advisor.
Hi Clemencia! Make sure you’re using OneNote for Windows 10 or the desktop version, since the web or Mac version doesn't support handwriting-to-text. Use a stylus to write, then select the handwriting with the lasso tool and tap "Ink to Text." Also, check in Windows Settings > Language that your chosen language has the "Handwriting" feature installed. Lastly, update OneNote and Windows, and try on a new page in case it's a glitch.
Best regards,