Since iGuRu.gr went online, we have been using permalinks that contained the date and title of the post, such as the following link:
http://iguru.gr/2021/06/06/sample-post/
Since iGuRu.gr went online, we have been using permalinks that contained the date and title of the post, such as the following link:
http://iguru.gr/2021/06/06/sample-post/
Today we decided to remove the date and leave only the title of the post.

Why
Because there is no reason anymore. Google used to ask for permalinks that contained the date and a random number to display the site's posts on Google News. Later he got back the random number, and shortly after he got back the date. The date is already in the structured data in each post.
You will need a coffee, and the Redirection plugin.
From the Settings / Permanent Links page (https://domain.name/wp-admin/options-permalink.php) change the links to the format you want:

In the case of iGuRu.gr we changed from "Day and name" to "Article name".
After the change you will have to make some changes. First the internet is full of your articles with the old links, and so in case someone clicks on a link the 404 will appear.
So install and open the Redirection plugin . You should add a redirect that will do the job for all the links in your database.
We will use regex:
Source URL: ^/\d{4}/\d{2}/\d{2}/(.*)
and
Destination URL: /$1

In case you use a different permalink format from "Day and name" see also the following regex:
Redirect date, name, and category permalink
/ 2020/01/02 / category / post-name ⇒ / post-name /
Source URL: ^/\d{4}/\d{2}/\d{2}/.*?/(.*)
Destination URL: /$1
See more from here
Finally, before closing, let us mention that if you are using xml sitemaps, you will need to disable and enable the plugin to create new links. This will be very useful for indexing Google. If you do not do it your sitemap will contain the old links.
Warning: If you care about your Google ranking, do not try to change permalinks.