Hello there, @yleyvagerva0865 ...
I am sorry to read that you are having a difficult time submitting assignments in your Canvas course(s). The first thing to always check is to make sure that you are using a supported browser. Generally speaking, this means you should be using an up-to-date version of either Google Chrome or Mozilla Firefox. See Which browsers does Canvas support? for more information.
Next, you may need to reach out to your instructor if you unsure of what is required of you when you submit work to him/her. We here in the Community wouldn't have access to your school's Canvas environment or your course(s) in question to know what your instructor is expecting of you. So, contacting your instructor would be your best option if you have questions about the content of the course. You can contact your instructor by following the steps in this Guide: How do I get help with Canvas as a student?
Finally, here are a couple video tutorials that may help that are related to assignments. Again, your instructor may have specific instructions for you about your assignments, but these tutorials will give you a good overview of how assignments work in the Canvas environment. After reviewing the below videos, you can dive deeper into how assignments work by checking out the written documentation.
I hope these resources will be of help to you! Please let us know if you have any questions about this information. Thanks!