When you start PassSafe, you need to create a PassSafe file to store your passwords. The PassSafe file is an encrypted file you can use to store your passwords. Each PassSafe file has a "Master Password". You need to know the "Master Password" to unlock the file and access the password details.
You would normally have a single PassSafe file, but if you have accounts for different purchases (eg: Personal Accounts and Work Accounts), you can create a PassSafe file for each.
The PassSafe file can be stored on either a local folder on your iPhone, iPad or Mac. If it is stored on a local folder, it will only be accessible from that device.
The PassSafe file must have a filename extension of "psafe". This will be added automatically by macOS in most cases.
You can also store the PassSafe file on iCloud drive, or a shared folder. For most people, it would be recommended to create the PassSafe file on iCloud drive so it can be accessed by each of your devices.