Difference between bold text and strong text.

Answer 1

the difference is just semantic. strong is for important text. you can use css to style b and strong differently to fit your needs.

Answer 2

The html tag <b> </b> was the old way to bold a text. It is obsolete but still works in browsers.

The <strong> </strong> tag does the same and it newer. It can be used

They do the same text styling.

The recomended way to format text is by using CSS. This way you also have more options, like bold, bolder.
font-weight: bold;