You should describe your webpage's content with 100-300 letters. A short paragraph which sums on the content or raise some interested to read more about the topic.
Do not use the same meta description text for several pages. Each should be unique. Google also picks up the meta description and may use it as the search result text for your listing. Take the extra effort and write a good meta description to ensure your not missing this easy seo step.
Read more: https://www.seocheck.io/page/meta-name-description

Great, you are not using ?underscores (these_are_underscores) in your URLs.
While Google treats hyphens as word separators, it does not for underscores.

Great your website is GZIP compressed. That saves bandwidth and improves your site's loading time.

Your webpage is compressed from 16 KB to 4 KB (72.2 % size savings)

Gzip is a server side compression method to save bandwidth and to load your site faster.
You should contact your host or admin and enable gzip compression by default.

Redirecting requests from a non-preferred domain is important because search engines consider URLs with and without "www" as two different websites. How to fix:
https://www.seocheck.io/page/www-and-non-www-domain

A sitemap lists URLs that are available for crawling and can include additional information like your site's latest updates, frequency of changes and importance of the URLs. This allows search engines to crawl the site more intelligently.
We recommend that you generate an XML sitemap for your website and submit it to both Google Search Console and Bing Webmaster Tools. It is also good practice to specify your sitemap's location in your robots.txt file.
how to fix: https://www.seocheck.io/page/sitemap-101

A robots.txt file allows you to restrict the access of search engine robots that crawl the web and it can prevent these robots from accessing specific directories and pages. It also specifies where the XML sitemap file is located.
You can check for errors in your robots.txt file using Google Search Console (formerly Webmaster Tools) by selecting 'Robots.txt Tester' under 'Crawl'. This also allows you to test individual pages to make sure that Googlebot has the appropriate access.
how to fix: https://www.seocheck.io/page/robots-txt-file

Pagespeed is an important ranking factor and a complexe optimization topic. Read more about website pagespeed here: https://www.seocheck.io/page/website-speed-test

A website's size is mostly defined by the required html code, images, css and javascript files.
Images have the most potential to reduce the required loading. Use a service like https://shrinkme.app
Css and javascript files can be merged and compressed.
Page size affects the speed of your website; try to keep your page size below 2 Mb.

Define a custom 404 page via .htaccess:
A customized 404 page can be designed however you like and also works as an marketing instrument. 404 page requests are happening by typing errors, moved pages, deleted content or similar. If your visitors end up on a custom 404 page you can give them options to continue to your homepage, signup for a newsletter, hide some easter eggs or redirect them to a sitemap.
Read more: http://www.seocheck.io/page/create-custom-404-page

Make sure your declared language is the same as the language detected by Google
This may affect your geo optimization. the html code is for an english website
This goes into the of your document of every page.

The declaration must be the very first thing in your HTML document, before the tag. It tells your browser how to render the code correctly. read more: https://www.w3schools.com/tags/tag_doctype.asp

Specifying language/character encoding can prevent problems with the rendering of special characters.

Keep your URLs short and avoid long domain names when possible.
A descriptive URL is better recognized by search engines.
A user should be able to look at the address bar and make an accurate guess about the content of the page before reaching it (e.g., http://www.mysite.com/en/products).