You undoubtedly want visitors on your website to take certain actions.
Maybe you want them to make a purchase, sign up, or fill out a form. When someone does something you want them to do, it’s known as a conversion. The visitor converts from browsing to taking the action you want them to take.
A funnel is the set of steps a visitor needs to go through before they can reach the conversion.
e.g. Check website, view the products , add to card and make payment.
The set of the above steps to conversion called a “funnel”
There are a lot of people who take the first step. Then, as the people continue along and take the next steps, some of them drop out, and the size of the crowd thins or narrows.