Hi there, @ATOZOOK.
I can help you with uploading your PayPal transactions to QuickBooks Online.
Yes, you need to use a supported file (CSV) to upload your transactions. If you're getting errors, I recommend reviewing the format of your file. When CSV file you can either use the 3 or 4 column format. For your guide, I recommend checking out this link: Format CSV files in Excel to get bank transactions into QuickBooks.
I'm also adding this screenshot for your visual reference.
Moreover, here's an article you can read more about manually uploading transactions into QuickBooks Online.
Once your PayPal data are now available in QuickBooks, you can open this article on how to review and categorize them.
If you have any other banking questions, please let me know by adding a comment below. I'm always here to help. Have a good one!