Online security is becoming increasingly important in today's world with the uptick in digital crime and online fraud. However, ask any random person on the street if they have used two-factor authentication and you will likely receive a blank stare in return.
Enabling 2fa on your accounts that support it is probably the quickest and easiest way to supercharge your online account's security. So what is 2fa? Well, it is pretty simple really - we all are already familiar with online usernames and passwords and Congratulations! right there you already have the first piece in place. That first piece is the "something you know" now to add another layer we are going to add "something you have" and this can be an authenticator app such as Google Authenticator, Duo or one of many, many others out there. These apps will provide you with a one time code that you can enter as part of your login process. Alternatively, more and more security concious people are turning to hardware tokens like those from Yubico. Please just stay away from SMS two-factor and if services you are using insist on it explain that is a very poor and insecure method of authentication(reasons for that are a whole different article that maybe one day I will get around to).
So which should you use? Really whatever you are comfortable with, just pick one. The authenticator apps are most likely the best choice for the beginner as they are free and pretty simple and straight forward to set up with your various accounts. If you are a more advanced user and have the spare $50 or so laying around then you'll probably want to check out the Yubikeys.
Pair either of these options with a password manager and you are well on your way to a reasonably secure online presence.
For a list of sites that use two-factor authentication check out this website