When you need to make something seem important, bold is the right choice.

You can use italics for foreign words like the Greek týpos — “reflection, form” and gráphō — “I am writing”, which together form “typography”.

Underlined text should be used with extreme caution as it stands out a lot.

Sometimes you may need to mark text as deleted. Strikethrough is the right choice then.

If you write about software, the option to mark inline code like `printf("hello, world\n");` comes in handy.

There are also subscript and superscript types that might be useful in texts about chemistry or math where you have to deal with things like H2O or x2.