HTML, or HyperText Markup Language, is the standard markup language used for creating web pages and web applications. It is a cornerstone technology predominantly utilized in the creation of web pages and interfaces. Most of the web content you see on your internet browser is structured through HTML concepts.

Understanding and mastering HTML involves learning how to use tags and attributes to format and stylize content. HTML tags, such as headings, paragraphs, lists, links, and more, denote how the content within them should be interpreted by the browser. It also involves understanding the HTML document structure, including the DOCTYPE declaration, HTML head, and body.

Companies looking for candidates proficient in HTML are essentially seeking individuals who can create, design, and manage the look, layout, and features of a website. This proficiency is crucial to jobs like web developer, software engineer, front-end developer, and many other roles in the tech industry. These individuals are capable of converting design mock-ups into stunning, fully functional websites, enhancing user experience through effective web design and navigation.

Candidates with proficiency in HTML should have a good understanding of other related tech skills such as CSS (Cascading Style Sheets) and JavaScript, which add style and interactive features to websites respectively. A foundation in these skills aids in the creation of more visually engaging web pages and applications.

Moreover, familiarity with web standards and prototyping tools like Adobe XD, Sketch, or Figma will enhance your capability in HTML. Knowledge of SEO (Search Engine Optimization) principles is also advantageous as it's important to craft websites that are not only visually appealing but also optimized for search visibility.

In summary, mastery of HTML offers an essential skillset for anyone aspiring to work in the field of web development and design. It is vital to stay updated with the latest HTML standards and trends as the language continues to evolve along with the web itself. Working proficiency in HTML, coupled with other complementary tech skills, can make a candidate highly competitive in the expansive job market of technology and web development.