If your company need a document to be uploaded to support your leave request, this will be shown when you go to request the leave.
Start by creating your leave by entering the type of leave, date range and a note if needed. Once you hit the blue tick in the top righthand corner, if the leave type needs a document, you will be sent to the page below stating you need to upload a document for the leave type.
To do this, simply click 'Upload document' and you will be prompted to take a photo or upload one from your phone. Once you have done this, you will get a notification saying 'Upload successful' and you have completed your leave request.
If you are manager, you can see the uploaded leave document to confirm this is what is needed and approve or reject the leave. You can find out more with this article.