Just as you might expect, “autosave” is a feature by which software automatically saves or records a copy of the file that you are working on without the user having to do anything.
In every version of WordPress released beginning with version 3.6, WordPress will autosave any work that you are doing on a post or page every 30 seconds. That way, if you lose connection to the internet or your computer suffers a malfunction, your hard work will not be lost.
Note: Every time WordPress performs an autosave, it will create a new version of that post or page called a revision. These revisions will be listed in chronological order, allowing you to easily go back to an earlier version of your post or page if you so choose.
From the admin area, WordPress does not allow you to directly control how often the autosave feature is activated, but you can change the frequency (or delete it altogether) by editing the “wp-config.php” file. The relevant function is known as “WP_POST_REVISIONS”.
As with all modifications to the core code of a WordPress website, please make sure that you know exactly what you are doing before making any changes!
Please note that the frequency of the autosave function plays no significant role in affecting your site’s performance. If your site is having performance issues, then it is almost certainly unrelated to the WordPress autosave feature as it is a very short piece of code that handles very small files.