Why do so many login webpages seperate email and password fields? [duplicate]

1. Why are username and password on separate pages?
2. What is the number one reason to not reuse passwords for multiple sites?
3. What percentage of people use the same password for multiple accounts?
4. Why do users need to provide their password twice?

Why are username and password on separate pages?

The most common reason to put username and password on two different pages is to support both: single-sign on (SSO) (i.e. sign in with Google or a service like Okta) username/password login.

What is the number one reason to not reuse passwords for multiple sites?

Reusing the same passwords for multiple accounts is bad practice because it opens you up to credential stuffing attacks, which take leaked credentials from one site/service and use them on other sites/services. It's as if you had multiple houses and used the same lock and key for all of them.

What percentage of people use the same password for multiple accounts?

12. Almost two-thirds of people use the same password across multiple accounts.

Why do users need to provide their password twice?

It is to avoid typos. If you have to type the password twice chances are you'll make your password what you want. They want to avoid having people whose password is "blah" having to retrieve their password later on because they typed "blaj" by mistake.