There is a long list of services that support 2FA using the Pix Authenticator app, and the list grows every day.
How to set it up
9 out of 10 times, these instructions are enough. For more information read about 2FA in general here.
If you are looking for more specific instructions, there is this excellent post by the Verge that details the process for:
- Amazon
- Microsoft
- PayPal
- Slack
Many of those services also support 2FA using SMS messages instead of an Authenticator app. Make sure to set up the app version whenever possible, because it is more secure than using text messages.