There are a lot of plugins are available on WordPress to an embedded youtube video in your WordPress post/page. Here is simple Process to WordPress Post Add Youtube Video without any Plugin.
I have a Youtube Video Link “https://www.youtube.com/” if I Keep the Link in the post then Link only appear in the browser.
if we Keep the video, then you can see the video to understand the Process. I suggest to all blogger if you are writing tech blogs like WordPress, Joomla, Drupal or anything related code, at the beginning/ end of article try to keep the video that will show that how you did. what the procedure you followed etc, that will helpful for you and the viewer.
Let me Share the Steps to Add video to your Youtube Article.
Copy the Youtube Embedded Code. Located under the Youtube Video.
Go to your Article Page. Write a Test as Video [Not Recomender], because to identify the Location in Text View and to apply the Styles
Now go to Text View. paste the Embedded Code in the Place of Video.
if you switch the view to visual you can see the Video. Publish the post the Video appears on your Post
If you have any Queries Regarding this Please Write in Comment Section.