Orange and red circles in my finder document
I have a macOS Mojave and I've just downloaded a PDF file from the internet. When I placed it in another folder, I found those two littles circles (one orange and another red).
What do they mean?
Those are Finder Tags. Tags can have colours assigned and these show on the file in Finder when the file is tagged.
Remove tags from an item: Control-click the item or tap it with two fingers, then click Tags. Select the tags you want to remove, then press Delete.
https://support.apple.com/guide/mac-help/mchlp15236/mac