As of this time, the option to upload sales and expenses in bulk isn't available in QuickBooks Online. However, you can consider @plung's suggestion to import your sales and expenses.
You can also go to the Apps menu and find a third-party application from there. Here's how:
From the left menu, click Apps.
Search for a keyword in the Search bar, like "Data Importer."
Find and select a third-party app, then click Get app now.