Hello, maisiet.
Thanks for contacting the Community with your question about entering bank statements. I'm here to make sure you're able to get your bank transactions in QuickBooks Online for the dates you need.
As you have discovered, some banks only download the past 90 days worth of activity. You can enter transactions manually by uploading a file by following these steps:
1. Click the Banking tab in the left navigation bar.
2. Make sure the account you'd like to work in is highlighted in blue at the top of the page.
3. Select the drop down arrow beside of Update in the top right corner, and choose File Upload.
4. This is where you'll add the file that has been downloaded from your bank.
5. Click Next and continue to finish the process.
This article will provide additional details about uploading more than 90 days of bank transactions: https://quickbooks.intuit.com/community/Banking-and-bank-feeds/How-to-upload-more-than-90-days-of-ba....
With this info, you'll be able to view the data you need for banking in your QuickBooks account. Let me know if there's anything else I can assist with.