Since version 10, Password Depot uses the file format pswe. This format can be used on all devices, including PCs, Macs, and smartphones.
If you store your password file in the cloud (e.g. Dropbox, OneDrive etc.), you can open the same file from different devices. This eliminates the need for synchronization.
If you do not want to store your data in the cloud, transfer your .pswe file back to your PC and use the "Synchronize Files" function from the "Tools" tab to synchronize the two files.
See also How do I synchronize two databases?