It is truly upsetting to see how few people use password managers. I have witnessed people who always use the same password (and even tell me what it is), people who try to login to accounts but constantly can't remember which credentials they used, people who store all of their passwords on a text file on their desktop, people who use a password manager but store the master password on Discord, entire tech sectors in companies locked to LastPass, and so much more. One person even told me they were upset that websites wouldn't tell you password requirements after you create your account, and so they screenshot the requirements every time so they could remember which characters to add to their reused password.
Use a password manager. Whatever solution you think you can come up with is most likely not secure. Computers store a lot of temporary files in places you might not even know how to check, so don't just stick it in a text file. Use a properly made password manager, such as Bitwarden or KeePassXC. They're not going to steal your passwords. Store your master password in a safe place or use a passphrase that you can remember. Even using your browser's password storage is better than nothing. Don't reuse passwords, use long randomly generated ones.
It's free, it's convenient, it takes a few minutes to set up, and its a massive boost in security. No needing to remember passwords. No needing to come up with new passwords. No manually typing passwords. I know I'm preaching to the choir, but if even one of you decides to use a password manager after this then it's an easy win.
Please, don't wait. If you aren't using a password manager right now, take a few minutes. You'll thank yourself later.
Password is necessary for two-factor authentication. The factors of authentication are something you know (like a password), something you have (like a cell phone), and something you are (like a biometric).
An example of three-factor authentication would be this—imagine a spy going into a secret bunker. They need to scan their iris, insert a key card, and then enter a passcode before the door opens. This has all three factors of authentication; the passcode is something they know, the key card is something they have, the iris scan is something they are.
If it just sends a code to your phone, that's one-factor authentication (something you have). Anyone with your phone can get into your account. Unless, of course, your phone hides its notifications and you have a screen lock. Then that's actually two-factor authentication because you also need to know the phone PIN or have the biometric.
If it just asks for a password, that's one-factor authentication (something you know).
If it asks for your password and then sends a code to your phone, which you need a fingerprint or face scan to unlock, you have achieved three-factor authentication.
Edit: Interesting tidbit—in the USA, you can rent a mailbox at the post office to receive mail when you don't want to give out your real address. Useful for privacy reasons. I'm sure they have similar things in other countries. These mailboxes come with a key. This is actually two-factor authentication, because the keys usually don't have the mailbox number written on them! So you have to have the key and also have to know which mailbox among the hundreds at the post office it opens.
Wow, the PO Box analogy is the best, most simple way I've ever seen anyone explain 2FA. Thanks, I'm stealing that for when I need to explain it to my tech-illiterate family members for the umpteen millionth time :')