I imported my bank statement but used an incorrrect date format. I need to elete all the transactions with incorrect date.

Welcome to the Community forum, @anadia.

Let's go ahead and delete all the transactions with incorrect dates in QuickBooks Online.

You can tick the box to choose which transaction you want to delete and then utilize the Exclude option under the Bank Transaction tab. Here’s how:

1. In the left navigation panel go to the Transactions menu, then go to Bank transactions.
2. Click the bank account.
3. In the For review tab, tick the box for the transactions you want to delete and click Exclude.

Here's a photo as a reference:

For more detailed steps, you can check this article: Exclude a bank transaction you downloaded into QuickBooks Online

Additionally, once you already deleted or excluded the incorrect transactions you have to categorise them, and then reconcile your account so it always matches your monthly statements.

You can always tap me if you have additional questions about handling your transactions or any QuickBooks-related matters, @anadia. Take the best care always and have a wonderful weekend ahead!