When finished creating your website, you will publish it on the Internet.
This is the easy part. Once you've built and debugged your site, it's time to upload all your files to a remote server. Your web authoring software will almost certainly include a "File Transfer Protocol" (FTP) tool that lets you post your web files to an Internet Service Provider (ISP).
You'll also need a "Universal Resource Locator" (URL) -- the "domain name" that identifies your site on the web. Vendors that provide web hosting services allow you to register a URL in the international Domain Name System (for a price). In addition, of course, they'll charge you for storing your web files and connecting them to the Internet so people anywhere in the world can access them.
Some online web tools like Weebly will host your site for free (as long as it doesn't get too much traffic) but if you want a unique domain name, you'll have to pay for it.
There are (almost literally) a million organizations that provide paid web hosting and related services.