The search and metadata section contains settings for searching the site and URL aliases. Let's start with the search.
Drupal uses an index to search for faster searches. If you have many nodes on the site, then it will take a long time to perform a full-text search on all nodes during a search, the user will not want to wait 5 seconds while searching (not to mention 10-15). The index bypasses all the nodes in advance and writes the data to a separate table, according to which the search will be faster. Therefore, it is necessary to bypass all the nodes in advance by the indexer, otherwise they will not be displayed in the search.
Number of items to index per cron run. Here you can choose how short the search will search, the larger the number, the smaller the search index by volume and the faster to search, but the fewer words will fall into the index. There are fairly short 3-letter words in English, so let's leave this setting as it is.
CJK - Chinese Japanese Korean. This setting is needed only for hieroglyphs, you can turn it off if you think it is necessary.
Logging. By default, this setting is disabled, you can enable it if you want to track what queries your users are interested in. But you should not keep this setting constantly on, in case of an attack by spammers on you, they will try to search hundreds of thousands of times a day in your form, this will cause a spike in the records in your database, which can lead to a site crash in a week.
Search Types. Here, by default, search is only by users and by nodes, you can disable the search by users. You may also want to add a search here in terms of taxonomy here.
This page contains all the aliases URLs of your site. The path module itself, which provides these settings, is not as interesting as the pathauto module, which automatically sets the URL aliases to all content on the site. But I think we will consider the Pathauto module separately.