em tag in html code example

Example 1: html em vs i

i has the purpose of presenting something in italicised style.
em has the purpose of giving emphasis to the content.

In practice emphasised content is typically displayed italicised,
so the difference on the face of it is non-existing from a
presentation standpoint. However, emphasis is semantic while
italics is presentation.

Example 2: how to emphasis in html

this is how to emphasis

Example 3: em tag in html5

basically italic
You have to hurry up!

Example 4: em tag in html

em { 
  font-style: italic;
}