Hello Hisham Bin Mohamed.
Thank you for posting in Apple Support Communities.
We understand you're not receiving notifications when you receive new emails. We'd like to help.
First make sure all your notifications settings are correctly set up: Use notifications on your iPhone, iPad, and iPod touch
If you're continuing to experience the same thing, try the steps here: If you can't receive email on your iPhone, iPad, or iPod touch
This includes removing the email accounts from your iPhone which can help refresh the connection to the mail provider's servers.
Have a great day.