Password managers are a great line of defense against your online accounts being comprmised.
Quicky disclaimer, any password can be comprimised, the use of Multifactor Authentication should be your first line of defense.
Password managers are a great way to create complex passwords, for several accounts and store them in one place. This is not the same as creating an excel spreadsheet with all of your passwords. That's something I will always strongly discourage. Password managers such as Bitwarden create an ecrypted database for your passwords that is accessed with a master password, which can be protected via Multifactor Authentication
A good idea would be to take your current passord (or something similar) and check it on a website such as Kapersky Password Checker. This tool will tell if your password appears in any known databases, and how long it may take to crack.
Utilizing a password manager is fairly straight forward. You'll need an e-mail address, which will be used for verification and login. If you're using Bitwarden, you can install a plugin on your browser that you'll need to login to. The plugin will prompt you to save any passwords you enter, as well as provide a password generator to create complex passwords for you. The beauty of this product is that its free to use, and you only need to remember one password. If asked, I can't tell you my e-mail password, even my PIN for my banking. That's stored in my password manager and extremely complicated.
Apple has unvelied their password manager for iOS 18 Beta. The Passwords app will generate a complex password and save it. You can also add new login information, and access the app on your iPad, Mac, Vision Pro and even your Windows computer through the iCloud app
With MFA, complex passwords may not be so vital. Not all services we login to have an MFA option. For example, your Home Depot account. Also, if you're a person that is terrible at remembering passwords and uses the same one for everything, this eliminates having all of your online accounts jeapordized by having different, complex passwords for each service you use. It's also a great way to ensure you arent using a common password that appears on a hackers database. MyCat1978! is not exactly secure and may surprise you at how common it is.