Password Managers or password generator is used to manage passwords for apps and websites. Each password app either it may be desktop app or website app it will use an encrypting program to manage the passwords that you use . This can also be used as file encryption. Similarly some managing app uses password generator they will generator a password every time when a user uses it.
Is it safe ?
Except few apps most of the password managers or not safe . Most users are not aware of the encryption program that they are using in some worst case scenario some apps directly save the passwords to an database file and they encrypt it which more vulnerable because if any fault in decrypting the file can make your day bad .And also hackers can easily asscess these kind of files easily.
I strongly suggest not use any password managers /generator because when it comes on to online privacy is more important than anything.