I believe the OP is trying to make a login form of some description.
I was just trying to find out whether the question was how to code up a form in HTML / CSS, or how to create a fully-functoinal login system.
Unfortunately, this is not possible using only HTML and CSS.
You will need to use PHP, for example to validate the user's login credentials,as well as a database (e.g. MySQL) to store them in.
This is quite a big subject, but a simple Google search turns up a number of promising results to get you started: http://www.google.com/search?q=simple+login+form+php
Maybe you could look for a tutorial which you are able to follow.
Then if you get stuck or have any questions, just let us know and we'll be happy to help.