I have some pdf’s that were created by someone else and they show little corner markers where the margins are. Is there a way to do this with Libre Office?
I will attach a screen shot showing what I am talking about
You could try this extension which fakes crop marks, Crop mark » Extensions
Or maybe try a desktop publishing program like Scribus
@EarnestAl
I checked the extension but this seems to be imperfect. It is only a setting of some marks within the page format…
This could be the better choice because you have to enlarge the page format in the DTP application, say plus 3 mm on each side.
As a workaround for Libreoffice you could manually set the page format larger and then insert the given drawing object of the CropMark extension…
See here a professional sketch (German) for bleed etc: https://www.typolexikon.de/wp-content/uploads/2017/08/ausschiessen-einteilungsbogen.png
More information: Bleed (printing) - Wikipedia