Software installed in the user's computer, mobile device or in a physical unit that connects via USB. Password managers are built into Web browsers, and they are also available as a Web-based service, allowing for password retrieval from any computer, smartphone or tablet.
Advantage = Complex Passwords
The major advantage of password managers is that they create more complex passwords than users typically make up, and a different one is generated automatically for each website. Even when users create their own strong passwords with letters, digits and special characters, they often use a similar pattern on multiple sites.
Disadvantage = One Location
Although passwords are encrypted by a password manager, the one caveat is that all the passwords are in the password provider's server. One expects the most highly secured servers are employed, but if the servers were hacked, and they are from time to time, the crook has every password to every account people have.
Password Manager + Personal PIN
One approach to making a password manager more secure is to add a secret PIN at the end of each automatically generated password. Users have to manually append that PIN each time, but the same PIN can be used. If the password manager were ever compromised, the attackers would not have the full password, because the appended PIN is known only to the user. See
password and
FIDO.