Answers for "external Jquery file from your index.html"

html include jquery

<!-- Wrap inside the head tag -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>

js jquery include external script

// jQuery
$.getScript('/path/to/imported/script.js', function()
{
    // script is now loaded and executed.
    // put your dependent JS here.
});