Wikipedia is the free online encyclopedia that anyone can edit. And it exists already for 20 years.
When searching for VAT, this is what Wikipedia comes up with:
“A value-added tax (VAT), known in some countries as a goods and services tax (GST), is a type of tax that is assessed incrementally. It is levied on the price of a product or service at each stage of production, distribution, or sale to the end consumer. If the ultimate consumer is a business that collects and pays to the government VAT on its products or services, it can reclaim the tax paid. It is similar to, and is often compared with, a sales tax.”
And much more.
Source Wikipedia