How can i make a site through coding where people can post their own content from scratch

You mean like a blog or a wiki? There must be lots of tutorials on YouTube for many languages, you'd be much better searching there for something like “How to write a blog in ________”, where the blank space would be your language of choice.

Unless you don't know any language. If that's the case, you'd better start by learning one and create your site later using it when you're comfortable with it. You could look just for “How to write a blog” on YouTube and see which languages come up the most, watch a few tutorials, see which language looks better to you…

And then, if your first choice was PHP, use your second choice. 😜

PHP Jokes are only funny but not true.

@Grocker True.

But jokes aside, just watch a few tutorials for different languages and see which one you like best, don't matter if it's PHP or whatever.

But no matter which language you choose, try to learn good coding practices and try to learn about web application vulnerabilities and how to avoid them as early as you can. Even if you end up using a web framework, knowing about how can people attack your website and how to prevent it will be a huge step forward for you.

Content Management System, or CMS, would be good terms to search for