For business customers who would like to VAT number during checkout, here's where to find the option.
First, click on the "Buy Now" button on the website to open the checkout page.
In the checkout page, first enter your email address, country, and other information that may be required to move onto the next step. Then hit continue.
In the second page of the checkout process, you will see an "Add VAT" option on the left-hand side of the window. Click on this option, and you will be able to enter the information needed.
Please keep in mind that, depending on what country you are in, you may not see this option.