Hey there, byoungjoo,
Thanks so much for stopping by the Apple Support Communities. If I understand your post, when using the iOS versions of iWork apps like Numbers, Pages, and Keynote, you'll get an error -1000 on your iPhone. I'm happy to help!
Based on what you've described, I'd recommend going through the steps outlined in the Apple Support article If an app unexpectedly quits, stops responding, or won’t open - Apple Support for the affected apps.
If you still need help after that, please get in touch with Apple Support directly: Contact Apple Support.
Have a wonderful day.