The Easy way of uploading a file is simple case of just finding the element and typing the absolute path of the document into it.
It is mandatory that it works only when the textbox is enabled. So please make sure that the input element is visible. In the below example 'uploadsubmit' is the name of that element and in 'sendKeys()' we have to specify the absolute path of the content that we want to upload (that can be file/image/video etc).
Sample HTML Code should look similar to this :