An important part of SEO (search engines optimisation) is Page Title, a string of text defined by contents of the title element in the head section of the HTML document.

This is the part that you can see at the top-left corner of your browser called The Title Bar. Also can be seen at the bottom of your screen as a tab.
Very significant for search engines, as is the part that will stand out on the result page (headline of a search engine) being the link to your website and will also have the search keywords.

Is highly recommended that all pages have a unique Page Title, must be accurate , keyword rich, relevant to the page content, avoid stop words as: the, and, for, a, etc…, avoid keyword stuffing as it could get you penalised.