Welcome to the Community, @rthobhani. I appreciate the details you've provided and the steps you've taken in migrating your data.
When migrating data from QuickBooks Desktop (QBDT) to QuickBooks Online (QBO), it's important to note that attachments are not included in the migration process. This is because the two platforms have different interfaces that do not allow for seamless attachment transfer.
However, you can still manually import the attachments into each invoice and bill within QBO. This process can be time-consuming, but it ensures that all necessary documents are properly attached to their corresponding transactions.
Alternatively, you can use a third-party service to convert your data from QBDT to QBO while retaining all attachments. This may be a more efficient option, particularly if you have plenty of data to migrate.
After sorting this out, you can refer to these articles to get started with your QBO company:
Return to this thread if you have further concerns with migrating your data. The Community is available 24/7 to help you. Have a good one.