Good morning, @abuhumaira0909 Welcome to the Canvas Community. Thank you for posting your question. Please see the following Guides which may help to determine if your assignment has been submitted successfully.
- How do I know when my assignment has been submitted?
- How do I know when my instructor has graded my assignment?
Also, I'm not sure which web browser you are using, but it's generally known here in the Community that Google Chrome and Mozilla Firefox will be your best options when navigating around Canvas compared to other browser that are available. (Sometimes, assignments don't submit correctly with browsers like Internet Explorer and Edge.) Check out Which browsers does Canvas support? for more information.
Finally, you may ultimately need to contact your instructor if you continue to have difficulties submitting your assignment. You can do so by following the steps in this Guide: How do I get help with Canvas as a student?
I hope these resources will be of help to you. Sing out if you have any other questions about this!