Hello Bosse Nyden,
Thank you for visiting Microsoft Community.
I understand you're experiencing difficulties creating new documents in the Office application on your new iPad.
First, I recommend verifying whether the app is logged into an account with an active Microsoft 365 subscription, as this is essential for utilizing Office applications on an iPad. You mentioned being able to access Office on your previous tablet, which suggests you do possess a valid subscription. If you're uncertain which account holds the subscription, you may log in individually at account.microsoft.com/services to confirm the subscription status and expiration date. Once logged in and the subscription is activated within the app, you should be able to create new documents and access other editing features without issue.
Should the problem persist even after signing in with an account that has an active subscription, kindly share any error messages or screenshots in your response—this will greatly assist in diagnosing the issue. Please feel free to provide updates or further details at any time.
Best regards
Huy-K | Microsoft Community Support Specialist