Let's find out the reason the transactions are missing, don631.
After switching from Desktop to Online, you may notice missing transactions or reports that don't match. This is because some data can't be migrated during the conversion.
To know what are these, please see this article: What to expect when Transferring Your File to QuickBooks Online.
You can also check out this article to learn the things you should perform after converting your file: What to do After the Migration Process.
Additionally, I've included our Getting Started With QuickBooks Online guide for reference. From there, you can browse and read articles that'll help you set up everything in the program.
In case you need assistance in managing your QuicKBooks Online transactions, please don't hesitate to get back to this thread. I want to ensure everything is taken care of.