You can only drag and drop online PDF receipts, such as Uber receipts or email purchase receipts, into QuickBooks Online (QBO) using a web browser, info2216.
In the QBO mobile app, you can utilize the Snap Receipt feature to upload files or scan receipts to add your PDFs to your account.
Here's how:
- Tap the + button to access the Snap Receipt feature.

- Click the Camera icon.
- Choose either to Upload file or Snap receipts.

- Follow the on-screen instructions.

- Once done, tap Create expense from receipt.
You can also refer to this article for more detailed instructions on the process: Upload Your Receipts and Bills to QuickBooks Online.
If you require any additional assistance with uploading PDF receipts in QuickBooks Online, please don't hesitate to update us in this thread.