You can certainly upload files and share them with your accountant in QuickBooks Online. Before everything else, you'll need to add him/her as an accountant user first to access the My Accountant portal wherein you can send and share files.
Your accountant will receive an instruction email from us to get started with accessing your company. Once done, you can now share and upload documents if you go to the My Accountant menu. You can check this out for more information: How to use the My Accountant tab.
Also, when sending reports, you can just click on the Email icon at the top of your report and send it to your accountant. I've attached a screenshot for your reference.
Know that I'm here to provide further assistance if you need it. I want to help however I can. Have an amazing weekend!