Guide Line Help?

[Addison3389274810rd]

Hello, I am a student who is still learning the InDesign program. Last semester my instructor added these guidelines to the corners of my papers (I am not sure what they are, or if they are even guides). They only show up when I export my projects, though. They are invisible when I am working as well as if I print, but I need help deleting them off of my exports! I have attached an example below, please help! 

[Joel Cherney · Accepted solution]

Those are called "crop marks." They're usually used to tell the printer where to cut the edge of the page off. If they are appearing in your PDF exports, the checkbox is found in the "Marks and Bleeds" section of the "PDF Export Options" dialog that appears after you choose to export a print PDF:

[Addison3389274810rd]

That worked, thank you so much! 

[Luke Jennings3]

Here is a link to some useful information about page boxes:

https://www.prepressure.com/pdf/basics/page-boxes#:~:text=There%20can%20in%20fact%20be,equals%20the%....