This is not really an Archicad question so you would probably be best searching elsewhere for the answer.
You will need some synchronising software or maybe you could use a cloud based service (Dropbox, iCloud, OneDrive, etc.).
One of the forum moderators. Versions 6.5 to 25 Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10 Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10
I sync my Archicad project data through a cloud service. I have identical folder structure on both computers, which makes syncing data without any problems. This works best for computers on different locations.
For syncing data between computers on site I wouldn't suggest syncing, as that can cause problems if data is accessed and changed on more that one computer at the same time. A shared project data base on a server or NAS (with RAID 1 and/or cloud backup) would be better in such case. I'm talking about micro or small business environments.
Archicad 4.55 - 24 | HP Z800 | Dual Xeon X5667 | 48 GB RAM | Nvidia Quadro P1000 @ Windows 10 Pro x64