HTML tags can be classified in few categories block level tags and inline tags.
What is Block Level Tags?
Block level elements always starts on a new line and takes up the full width available. Example block level tags are <div>, <header>, <hr>, <footer>, <pre>, <video>
What is Inline Tags?
An inline tag does not start on a new line and only takes up as much width necessary based on the content
Example tags: <span>,<a>, <b>, <b>, <button>,<textarea>