A:Answer It should work that way as-is/out of the box. They're usually formatted with NTFS, which works fine plug-and-play w/MacOS, Windows, and most Linux distributions. I use all three platforms and generally leave the drives as they come: NTFS. Of course, different operating systems have slightly different rules about filename length, special characters, etc...
If you mean can one of these connect to BOTH a PC and a Mac at the same time, the answer is NO: this is just an external USB drive, not a network drive. It has a USB port to connect to a computer, not an ethernet port to connect to a network directly. However, you CAN plug the drive into a computer, and they set up that computer so it will share the drive/files w/other computers on your home network.