Hi there, @emmahuynh88
You can check on the Banking page if QuickBooks can connect to your bank.
- Click Add account.
- Search the name of the bank.
- Enter your username and password to sign in, then select Continue.
- Complete the security verification.
- Select Add new to create a new account.
- Then, select Connect.
If you're unable to find the bank, you can click the Request support for your bank option. I also added an article for you to learn more: How to identify the correct bank.
Here's an article about uploading your bank transactions that are beyond 90 days: Manually upload transactions into QuickBooks Online.
Thanks for dropping by.