Thats a Form input. Information is passed to servers either using form fields or cookies.
The server script get this information and process it, using it for queries to a database or whatever. Then it displays a page with the processed information.
There are two methods of passing information using forms. One is Get, which will display this information in the address (unless the field is a Password or button type) like you wrote, separating them with "?", like ?fieldname=value?fieldname2=value2 . The other one is Post, which will not show the information in the address.
I suggest taking a look at HTML Form coding to see how this is done inside an html. Here's a brief example, anyway
Submitting this will create this code after the script name:
?myname=itsecret
lol enough.