The keywords tag is a HTML element that should be placed in the head section of your webpage. It provides keywords relevant to the page it is included on, so search engines can categorize a site by these words. Most search engines (like Google) don’t use the keywords for enlisting your site though! Only some of them might. Most search engines do, however, use the keywords to search for misuse, such as with the inclusion of popular words that have nothing to do with the site. Since keywords don´t give a huge advantage, many sites choose not to include them. The Internet of Bots offers a full tutorial about how to correctly implement this keywords tag, by which users and search engines can make the best use of this part of a website.
<meta name="keywords" content="the, internet, of, bots">
This is a difficult question, since different developers have different opinions. The main thing is to place the title tag in (the top) of the head section. The Internet of Bots uses the following order as proposed bij Bootstrap 3:
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Optimization of the title tag - The Internet of Bots</title>
<meta name="description" content="The keyword tag is a HTML element... ">
<meta name="keywords" content="The, Internet, of, Bots" />