Can my passport for mac transfer files onto another mac or pc?

i just bought the my passport wd today and already reprogrammed it to accept videos and other files by just dragging them in. when i unplug it and plug it back in, the files are still there so i know they’re saving. but when i plug the hard drive into another computer, none of the files are showing up. is this just because im trying to view mac based files on a pc? and if not, how can i convert/ transfer them onto the pc?

the main reason i bought this thing was so i could move vidoes and music from one computer to the next, while also having all my media saved on one device. is there no way it can transfer files to another computer, or is it solely a back up machine? i have no idea how to do anything regarding these questions and IF you can help i would greatly appreciate a slight walk through, if possible. 

thank you to anyone that answers…

Well you can format the drive FAT32 and it will work on both but the biggest file it will accept is 4 gig. You can formatt it NTFS (for Windows) then download and install on your Mac NTFS-3G and it will allow the Mac to read and write to the Windows formmatted drive. NTFS-3G is free the similar software to make Windows use a Mac format drive is pay.