When you want to direct users to your website, you’ll use what’s known as a permalink. This is a URL comprised of your site’s domain name, as well as a slug (the part of the URL at the end, which generally describes the content). The way permalinks are structured greatly influences their effectiveness.
While permalinks are ‘permanent’ by nature, they can be changed if necessary. When done properly, this type of change can reap major benefits for your website, including a boost in search engine rankings and an increase in site traffic.
What Is a Permalink?
A permalink is a “permanent hyperlink” to a specific web page. It’s ‘permanent’ because the link isn’t meant to be changed, as this would create dead links.
Most permalinks look like this:
https://www.mywebsite.com/blog/blog-post-1
Aside from directing users to the specific web page, permalinks also tell users what the page contains (for example, a blog post).
WordPress Permalinks?
Each Content Management System (CMS) has its own way of structuring permalinks – including WordPress. For example, when you create a new post in WordPress, one of the standard permalink structures is:
http://www.mywebsite.com/2018/02/sample-post/
This tells users that the post was created in February of 2018, and includes the name of the content (sample-post).
One of the great things about implementing permalinks in WordPress is that you have the ability to alter their structure. In the WordPress dashboard, navigate to Settings > Permalinks. Here, you can choose from a variety of different structures:

Although the WordPress permalink settings do provide a variety of options to choose from, frustrations may arise if you wish to use a different combination. For example, what if you want to include the year the post was published and the name, but not the day or month? Fortunately, this problem can be solved with the use of WordPress custom permalinks.
WordPress Custom Permalinks/URL Structure
There are two ways to create custom permalinks in WordPress. The first changes the URL structure, while the second enables you to alter individual page or post URL slugs.
To change the overall structure, return to Settings > Permalinks. Click the radio button next to Custom Structure, and select the tags you’d like to include:

Once you’re done, hit Save Changes. Now all posts on your WordPress site will follow this new structure.
If you’d like to alter the URL slug for individual posts and pages, the process is also simple.
On the back end of your website, open the editor for the page or post in question. Below the title, you’ll see its Permalink:

Simply click on Edit, and change the end of the URL to whatever you’d like.
You can change this permalink before or after posting the content, but it’s highly recommended not to alter it afterwards unless absolutely necessary. This can make all uses of the old URL result in errors. You’ll need to set up URL redirection to avoid that issue (we’ll cover how to do this later).
Parent/Child Pages
Another aspect that can impact URL structure is parent/child pages. These are pages that follow a particular hierarchy on your website.

For example, when you visit a ‘regular’ or parent web page, the URL structure is as follows:
www.mywebsite.com/web-page
However, when you visit a child page, there is an additional element to the URL structure. For example:
www.mywebsite.com/parent-page/child-page
This is known as a breadcrumb, which helps your reader understand exactly where they are on your website and how to return to any previous sections (such as the parent page).
While you can remove the parent-page aspect of the URL by using WordPress plugins, it’s best to keep it intact. This is for the benefit of your users, as well as search engines.
The information on this page has been taken from https://wpengine.co.uk/resources/wordpress-permalinks/