Then why are you here? It sounds to me like you want to modify the site somewhat but don't know how and I assume that you do not have an ongoing maintenance contract with the developer with whom you contracted to develop your site. There is no such thing as a web site that does not require some knowledge of HTML and CSS. A good CMS can minimize the need for such knowledge, but there will always be the desire to fine tune a page. If you need help with your site, which you do at this time, an understanding of the basic language of HTML/CSS and page layout will help you communicate better with coders and them with you.
If you were promised a quality coded site that you could maintain with no need for any knowledge of HTML and CSS, you were misled and overcharged, period.
(1) "id"s are unique to a page. There can only be one idName on a page. This page contains 50 copies of this
<b id="docs-internal-guid-6f35ec11-b5d8-2756-a5bd-ad910d999f3e"> (that accounts for 50 of the errors).
<p> </p> as spacers between paragraphs? I believe this is a WordPress generated error. The validator does not flag this as an error because the "p" tags are balanced, but is inappropriate code, nonetheless. A WordPress person who is familiar with the WP code generator can help with the solution.
(3) Most tags (elements) such as
<div> tags are required to have a closing tag. Thus,
<div>...</div> is the way they are found in the HTML>. Certain tags are known as empty tags, such as
<meta>. Empty tags do not require a closing tag because they are not containers in the normal sense of the word. The validator shows one closing
</img> tag on your page. Also, HTML does not require empty tags to have closing slashes. (Closing slashes on empty elements is a carry-over from XHTML). They do not trigger an error in the validator, but again represent a dated code practice.
(4) HTML tag attributes must use straight single or double quotes. NO curly quotes allowed. One can use curly quotes in content, but not around HTML/CSS keywords.
One of the 10 invalid meta tags identified by the validator is
<meta name=”keywords” content=””/>, which also includes a useless closing slash.
Although you are not planning to write a web site, I still recommend taking an introductory class in HTML and CSS. Familiarize yourself with the basics. Since your site is based on WordPress, you might need to read the instruction manual for coding WordPress so you will gain more knowledge of the WordPress way pages are built or at least read some tutorials. A WordPress person can offer better recommendations that I. I've already harped about indentation. To that let me add the many empty lines (white space) in the code. They should be eliminated as much as reasonable. This is just a waste of space:
<div class="row newsletter-header
<h1>Learning languages effectively </h1>
<div class="row newsletter-bg
it goes on.
Finally, it's just human nature... when you need help, the better you can present some knowledge of the language of HTML and page construction, the more enthusiastic volunteers will be to help you work through issues.