You can’t insert or upload YouTube Videos in WordPress posts or pages, but you can only embed the Video in your WordPress blog, post or pages.
On a personal note, I have tried numerous process and ways on how to insert YouTube video in WordPress blog of mine but none worked, until one of my trials worked.
Before this time, I felt frustrated, even tried some recommended plugins but all could not live up to expectations. I hope the following guidelines will be of help.
The following step by step guidelines are of importance in other to get it done.
 On the particular post[s] or pages you want to insert the YouTube Video, go to edit i.e. edit the post or page
 On the edited portion, there are two template of the post to be edited i.e. you will see “HTML or Text and Visual”
 Click on “HTML or Text” and you will be presented with the Hypertext mark up language of the page
 Now, go to YouTube i.e. to the video of interest, click on it as if you want to watch it.
 Now, while playing, go to the shared section, try to locate “embed”, click on it and copy out the code. Please note that you have to uncheck the portion that says ‘ Show suggested videos when the video finishes’. Secondly, you will see various video sizes, chose the size that you think will fit into your post very well. For instance, in the video below, I chose 640 by 360.
 Go back to your edited WordPress HTML post and paste the code at any location of your interest.
 Click on publish or update and there you go
NOTE: Immediately you paste the code in the HTML page, don’t touch or edit any other portion of the page, doing such might make the video not to show. Simply update and publish the post straightaway.
Feedback and suggestions
Do you know of any other solution or the use of credible plugins on how to insert YouTube video in WordPress? please, kindly share in the comment section below. Thank you