iPad Air spelling and auto-correction not working

C1980 wrote:

Settings> keyboard > English & Romanian

If by chance you are using a bilingual keyboard, you can try going back to monolingual versions.

Managing Bilingual Keyboards - Apple Community

The spelling issue is for Facebook and Youtube

If you don't see the issue in Apple apps, then you need to contact the people who make the apps where it occurs.

From your post, it seems like English may well not be your first language. Tell us all about your language and region, dictionary, and keyboard settings. They are likely responsible for the issues you have.

Are you using the English keyboard and English language when you are checking English spelling?