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.
You can also store the PassSafe file on iCloud drive, or another cloud or 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.