I need to import last 2 years' AP, Bank and other journal transactions. Can I do it all these together or import one-by-one only?

In QuickBooks Online, AP and Journal entries transactions can be imported one by one, Geetika-Arora. 

It's possible to import AP and bank transactions in QBO, which can be imported using a CSV format. Make sure the number of transactions remains within the limit of 1,000, as that is the system's maximum capacity. 

You may also refer this article for guidance on: importing journal entries into QBO.

Visit this link for more details: Frequently asked questions about importing data into QuickBooks Online.

I'll share this article to help you with: customizing reports in QBO.

We have a team of experts who can offer personal guidance on managing your journal transactions and as well as in teaching the best bookkeeping practices to increase your efficiency. Check out QuickBooks Live Expert Assisted for more details. 

Feel free to reach out if you have any additional questions about this or other topics. We're here to help.