What is difference between strong and bold in formatting

Answer 1

In HTML5 <strong> and <b> both exist and have a different meaning.
The <b> tag is for "offset text conventionally styled in bold". If you read deeper into the details you'll see it adds, "without conveying any extra emphasis or importance".
<strong> is different. It "represents a span of text with strong importance." There is semantic meaning of importance here. In fact, a <strong> tag within another <strong>tag has even more importance.

Answer 2

they both look the same, so b is used a s a shortcut for strong, but strong is
when you want to emphasise something important, and b (bold) is a way of drawing attention to certain words.