If you are looking for a way to start fresh in Quickbooks Online (or any other bookkeeping software like Sage for example) without importing every single transaction, the solution is simple enough.
Disclaimer: This does not replace your existing records but it will be accurate. By law in Canada you need to keep your records for 6 years.
Step 1
Gather your final reports from the end of the last fiscal year.
The Trial Balance report will make your life easy. Balance Sheet and Profit and Loss together are fine, but you will need to understand debits and credits.
Step 2
Set up (or import) your chart of accounts with no balances.
Create no transactions of any kind.
Do not import invoices or bills or balances.
Step 3
Create a journal entry using reports.
Positive assets are debit and normal liabilities are credit (negative assets are credit, overpayment of liability is a debit). Income accounts are credit, and expense accounts are debit, the sum of this is the profit of the year (or income summary). Retained earnings are a credit as long as it is not a deficit.
If you enter Accounts Payable (AP)/ Accounts Receivable (AR) the way this method suggests, do not also recreate open bills/invoices as this will create a discrepancy. Use a dummy (fake) vendor/customer and when the payments are made, categorize them to the same dummy vendor/customer and appropriate AP/AR account. Do not categorize these new payments as expense/income accounts because that will create duplicate data and not lower your AP/AR balances.
Step 4
Confirm that what you did worked and that debits and credits are correct.
Generate a trial balance, profit and loss (income statement), and balance sheet for the last fiscal year. Quickbooks Online automatically turns the profit of the year into retained earnings, and you will see the change in balance by running a report for the day after fiscal year-end.
Note: Consult with your accountant in regards to everything you are doing and ensure that no adjusting journal entries are missing.