First, a permalink is the direct address for a page or post on your website. It is the ‘permanent link’ to a specific piece of content on your site.
When you first set up your installation of WordPress the permalink structure is set to Day and name. This will look as the example in the graphic – http://yoursite.com/2021/04/11/sample-post/
I prefer to use simply Post Name – http://yoursite.com/sample-post/ in other words, the link to your article will be your website url followed by a slash and the title of your post/page with the spaces between the words replaced with dashes (this is referred to as the post/page slug).
This latter setting seems to be preferred for search engine purposes and for ease of use of your website visitors.
What if you have been operating your website for a while, have several posts/pages and have just found out that your permalinks are set to the older default that includes a question mark and database ID number? Can you change the permalink setting retroactively? The short answer is Yes. However (there is always a however, isn’t there?)…
Changing the permalink structure of an established WordPress website will immediately change the url of every published page and post and media file on the site. That means that anyone who has linked to content that you have published will now have a broken link. To fix this condition you will need to tell the search engines that each page/post has been permanently moved to a new address. This is referred to as establishing a ‘301 redirect’ and involves giving the search engines the old address, the new address and the designation that it is a permanent change of address. Plugins are available in the WordPress Plugin Repository and can be found by searching for ‘301 redirect.’ In some cases this redirect can be accomplished using specialized instructions in an htaccess file in your hosting account root directory but that requires specialized knowledge and experience and is best left to professional developers.
NOTE: There are some eCommerce or other specialized plugins that may require a specific permalink structure in order to work properly. It is best to do your homework and plan for your website’s final configuration before you add a lot of content and make your website live to the public with the wrong permalink structure.