<div> </div>
The div tag is used to group various other HTML elements. It is a block level element. We can say it also create a block.
Ex:-
<div> This is a Div Tag </div>
<div>
<h1> Heading </h1>
<p> Para </p>
</div>
<span> </span>
The span tag is used to group inline elements. It is an inline element.
Ex:-
<p> I am example of span tag </p>
<p> I am <span>example of span tag</span> </p>