There are many online platforms that you can use to build and launch a website.
https://www.squarespace.com/
https://www.wix.com/
https://www.wordpress.com/
https://webflow.com/ (also see their webflow-101 course)
Go ahead – and explore these platforms. Play with them. The available templates on these platforms implement a host of design practices that are considered standard and protect you from making bad beginner mistakes.
It helps if you have a goal in mind. Like, a website for your Mom’s cooking recipes. Or an online portfolio for your friend who might be into Photography or some Art.
If you can explore a bit of HTML and CSS, these platforms offer more flexibility to you!
Once you setup your site, you may want to buy a domain for your website. Head to service providers like https://www.godaddy.com/ and buy a domain. If you are just playing around, buy a cheap domain for a year. If you are serious, buy for 3 to 5 yrs and remember to renew it.
Once you buy your domain (like mymomsrecipes.com), you can link the domain easily to your website on SquareSpace or Wix or WordPress.
Note
What you learned here is just how to create and launch a simple website quickly. If you wish to be a professional website developer, you need to start exploring really interesting topics like Information Architecture, Wire-framing, Story Boarding, UI/UX, Accessibility & Inclusive Design Practices, Design/Build/Test/Learn cycle, A/B Testing, and Deep Tech Chops in HTML/CSS, Google Analytics and similar tools, and lot more.