In Drupal, by default, the URL path for taxonomy term page is ..../taxonomy/term/3. Well, as you can see, the URL is not very meaningful. However, by installing Pathauto module, you can convert that URL into something like ..../taxonomy/term/python, which is much more meaningful to Google web crawlers.

Setup URL alias pattern

1. After you installed and enabled Pathauto module, navigate to Configuration > URL alias.
2. Under the Patterns tab, click on Add Pathauto Pattern to create a new pattern.
3. Set the Pattern type to Taxonomy term.
4. Set the Path pattern to the way that you like, e.g. taxonomy/term/[term:name]. Note: The Browse available tokens link will show you all the possible patterns that you can use.

Regenerate URL

1. After your pattern has been set, head over to the Bulk generate tab.
2. Select Taxonomy term.
3. Generate a URL alias for un-aliased paths only

Clear the cache

After you regenerated all the URLs, you will not see the effect until you clear you system's cache. Navigate to Configuration > Performance and then click on Clear all caches.