Hi there gaias_worship-li,
Thanks for reaching out about prior bank transactions. QuickBooks Online is a great tool able to assist in keeping track of sales and expenses so you can see the profit of your company. I can provide some information about importing prior transactions.
To import transactions from a period earlier than what QuickBooks Online can fetch using the bank connection, you would need to import it using the steps outlined in this article.
If you have any other questions, feel free to reach out here.