How does a blog create and store the data?

I am fairly new to web development and flask and created a few beginner level projects. Now I am thinking of making a blog but the problem is all the tutorials I have ever seen have shown to create a very minimalist type of blog, where a user writes some text in textfield and it gets stored in a database and then displayed on screen.

My question is how does a blog exactly works.

• How does one write a blog on Front end. Is the writer given a markup type of display to write as in Stack overflow or something else?
• Is the blog post saved in database or does it create a HTML file with that post and add it to route?