Hi @Mohammed Abed,
I will recommend you to use SPFx extension to inject CSS/JS to hide the SP Header. Please refer to the following extension
You can deploy the extension in your site and inject css file to edit your page.
Here is a nice article similar with your requirement, please make a reference
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.