does jquery have to be in document ready code example

Example 1: jquery document ready

// jQuery document ready
$(document).ready(function() {
    
});

Example 2: document ready

// A $( document ).ready() block.
$( document ).ready(function() {
    console.log( "ready!" );
});

Example 3: document ready jquery

$(function() {
  // Handler for .ready() called.
});