如何在PHP页面之间传递数据?

In a nutshell on "page1.php" I have a calculator that consists of an HTML form, and then the PHP code totals the input and displays the total price. Below the price, it also displays a link to "page2.php" which contains an HTML form where they can enter their contact information. Upon submitting the form the selections they made on "page1.php" in the pricing calculator as well as the contact info on "page2.php" are emailed to me, and they are redirected to the home page. In a nutshell on "page1.php" I have a calculato