A landing page is a page on your website that has the one goal of getting the viewer to take a very specific action. Of course all pages should have a CTA (or call to action) at the bottom (and maybe throughout) that directs the user journey, but a landing page speaks specifically to that ONE CTA and its primary goal is to get people to click that button at the bottom.
A landing page is usually used to generate leads (ie. a page that has a freebie on it) but can also be a sales page with a very specific goal.
You can create a landing page through your email marketing platform like Flodesk and Convertkit. The nice thing about these platforms are they make it SUPER EASY to design effective landing pages. See some examples below ↓
Another option is to create your landing page directly on your website platform like the below example. You may be able to find a template through your website builder. Check out my FREE landing page template for SQUARESPACE!