missing bank transactions

Can you download the bank statement in csv or pdf from your bank?

If certain transactions haven't automatically synced from your bank, you can manually upload transactions directly into QuickBooks Online to ensure your financial records are complete and up-to-date, DCP. Follow the steps given below.
 

Before manually importing the transactions, Chrea is correct. You must first download or save those transactions from your bank's online platform in a CSV format.
 

Once you have the CSV file, here's how to upload it in QuickBooks: 
 

1. Go to Transactions, then Bank Transactions.
2. Select the account you want to upload the transactions into.
3. Choose Upload from the file from the Link Account dropdown.
4. Drag and drop or select the file you downloaded from your bank and click Continue.
5. Follow the given steps to proceed.
6. After that, confirm by selecting Yes, then Done to complete the process.

If you still can't find the transactions, consider opening this material for more guides on how to check different areas of your accounts to find missing transactions in QuickBooks Online (QBO): What to do if you can’t find downloaded transactions in QuickBooks Online.
 

Additionally, here's an article if you want to learn how to categorize transactions uploaded to QuickBooks to provide a clear and organized financial view of your business: Categorize online bank transactions in QuickBooks Online.
 

Moreover, if you have lots of transactions to manage, consider QuickBooks Live Expert Assisted. This service offers the assistance of certified professionals who can help streamline your bookkeeping processes. 
 

Would you like to learn how to set up bank rules to categorize transactions in QuickBooks, or do you have questions about missing transactions? Let me know in the thread. I'm here to assist you.