Should we send both username and password after registration?

1. Why do users need to provide their password twice?
2. Why is it not good practice to send login details in GET request?
3. Why split username and password?

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.

Why is it not good practice to send login details in GET request?

Even if the user and password weren't stored in the browser's history (which they are, as URL parameters) this makes it extremely easy for any hacker to steal your information.

Why split username and password?

By splitting up the process, the site is collecting as much information about the account as possible, so that they can be 100% sure. In addition, most of the time people remember their password, but not their username, or vice versa. Separating the process makes it easier for them. Save this answer.