QB is only downloading my transactions for the past 3 months. How do I import my transactions for the past year?

I can help you import the past year's banking information to your account, teriparker30-yah.

When you connect your bank to QuickBooks Online, it automatically downloads 90 days' worth of transactions. You can manually import the data from the previous year using one of the supported file formats. Please note that the maximum file size is only 350 KB. This will allow you to bring them into QuickBooks without any hassle. 

When you're ready, you can upload them into the program. For accounts connected to online banking:

1. Go to  Banking and select Banking.
   
2. Select the blue tile for the account you want to upload the transactions into.
3. Click the Link account dropdown and then Upload from file.
   
4. Pick Drag and drop or select files and select the file you downloaded from your bank. Then select Continue.
   
5. In the QuickBooks account dropdown, select the account you want to upload the transactions into. Then click Continue.
6. Follow the onscreen steps to match the columns on the file with the correct fields in QuickBooks. Then select Continue.
7. Choose the transactions you would like to import. Then tap Continue.
8. Click on Yes, then Done.

If your bank isn't linked to online banking yet, please proceed to Step 4 in this article: Manually upload transactions into QBO.

After that, you're ready to categorize and match your entries. This task assures that you're putting them in the right accounts and avoiding any possible duplicates.

I'm still here to help if you need more insights about banking or other QB concerns. Just put the details in the comment section below, and I'll get back to you as soon as I can.

@teriparker30-yah 

Another option, use MT Online or one of the converter tools (e.g csv2qbo) as a workaround.

https://www.moneythumb.com/?ref=110