My prefix in Korean or Japanese causes an error.

Numbers are drawn with a font built into the PDF format, which only covers Latin characters. Stick to things like "p." or a dash.

I don't want a number on the cover page.

There's no way to skip specific pages. Remove the cover with Delete PDF Pages, number the rest, then put the cover back on the front with Merge PDF.

For documents that continue from another one. Start at 5 and the first sheet is 5, the next is 6, and so on.

The new numbers are added on top — the existing ones aren't removed. Choose a different position to avoid overlap, or clean up the originals first.

Documents assembled from several sources usually end up with broken numbering or none at all. If nobody can say "look at page 7", meetings slow down.

This tool prints a running number on every page. You choose the position, the starting number, and any text before or after it.

My prefix in Korean or Japanese causes an error.: Numbers are drawn with a font built into the PDF format, which only covers Latin characters. Stick to things like "p." or a dash.
I don't want a number on the cover page.: There's no way to skip specific pages. Remove the cover with Delete PDF Pages, number the rest, then put the cover back on the front with Merge PDF.
Why would I change the starting number?: For documents that continue from another one. Start at 5 and the first sheet is 5, the next is 6, and so on.
What if the document already has numbers?: The new numbers are added on top — the existing ones aren't removed. Choose a different position to avoid overlap, or clean up the originals first.