Google Analytics is a free tool from Google that shows how many people visit your website, where they came from, and what they do once they arrive. You add a small snippet of code to your site, and it quietly records the traffic.
For a small business, this is how a website stops being a guess. Instead of wondering whether anyone found you, you can see that most of your visitors came from a Google search, that one particular blog post brings in the most readers, or that people drop off on the page where you ask them to book. It turns a vague hope into something you can actually read and act on.
The numbers are only useful once you know how to read them, which is why a figure like bounce rate means little without context, and why the ones worth watching are tied to a real goal like a call or a booking. I set up analytics on a build so the traffic is measured from day one, because you cannot improve what you were never able to see.