using custom fonts in html code example

Example 1: import font css

@font-face {
  font-family: "Open Sans";
  src: url("/fonts/OpenSans-Regular-webfont.woff2") format("woff2"),
       url("/fonts/OpenSans-Regular-webfont.woff") format("woff");
}

Example 2: how to add font otf format in html

/*default version*/
@font-face {
	font-family: 'lovelyFont';
	src: url('fonts/lovely_font.eot'); 
	src: 
		local('Lovely Font'),
		local('Lovely-Font'),
		url('fonts/lovely_font.otf') 
		format('opentype');
}
/*bold version*/
@font-face {
	font-family: 'lovelyFont';
	src: url('fonts/lovely_font_bold.eot'); 
	src: 
		local('Lovely Font Bold'),
		local('Lovely-Font-Bold'),
		url('fonts/lovely_font_bold.otf') 
		format('opentype');
	font-weight: bold;
}
/*container element*/
div { font-family: 'lovelyFont', sans-serif; }
/*span elements inside the container div*/
span { font-weight: bold; }