The basic HTML structure include the head elements among them the title and description tags.  Currently it is not possible for an administrator or teacher to set these tags specifically for each page in Moodle. This is very surprising as this is a basic element that should be present on every page of any Web site on the planet!

Furthermore, one should have a complete control on the title page which is of paramount importance for SEO reasons.
In particular, the first word of the title is the most important one. The title of a page should be specific to the page. Having the same title for different pages (or a similar one) is not good because search engines will have difficulties to distinguish pages whose title are similar and thus will give them less importance.

The description tag is also important, so do other ones, see https://www.w3schools.com/tags/tag_meta.asp
or https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base

See also
Nine Best Practices For Optimized < title > Tags
http://searchengineland.com/nine-best-practices-for-optimized-title-tags-111979

For example, for URL pages, the structure of the title page is as follow (see mod\url\locallib.php)

$PAGE->set_title($course->shortname.': '.$url->name);

From my point of view it should be changed to

$PAGE->set_title(url->name);

See also:

• In mod/ressorce/localib.php:
  $PAGE->set_title($course->shortname.': '.$resource->name);
  should be changed to
  $PAGE->set_title($resource->name);
• in mod/page/view.php
  $PAGE->set_title($course->shortname.': '.$page->name);
  should be changed to
  $PAGE->set_title($page->name);

and so on....

Related issues:
MDL-50376
MDL-41745
MDL-49927