I have a lot of notes, how to copy them to iOS fast?

NotePlan saves your notes locally on your device. On iOS (iPhone or iPad) you can find the files using the Files app > On my iPhone/iPad > NotePlan. If you have a lot of notes (2000+) and/or a lot of big images and files inside your notes and it takes too long to sync them all initially to your iPhone or iPad, you can also copy them from your Mac:

1. Create backups, just in case.
2. Connect your iPhone or iPad to your Mac using a cable.
3. Then open Finder and find your iOS device under "Locations".
4. Click on the device and open "Files" in the tabs.
5. Find NotePlan in the list and expand it. 
6. Close NotePlan, if it's running or deletions will be propagated through the sync
7. If you already see folders there, delete them all.
8. On your Mac, open the location your notes are saved (use "Show in Finder" in the note menu top right).
9. Now drag at least the folders "Notes", "Calendar" and "Caches" into your iOS device.
10. When the copy process finished, you can open the app on your iOS device and it should have all the notes.