I add twice and the payment method cash how can erase one

Hello there, telloluz.

The QuickBooks accounting software helps with the daily bookkeeping and accounting tasks that many business owners do themselves. QuickBooks does this by automating or streamlining basic tasks, which also reduces transaction errors. However, mistakes such as duplicate payments can still happen. If you accidentally enter a payment twice in QuickBooks, you can remove the duplicate payment by voiding or delete them in QuickBooks. I'll guide you how.

1. Go to Sales or Expense.
2. Find and open the transaction.
3. Add a note to the Memo or Message section if you want to include the void or delete date.
4. Select More in the footer and choose Void or Delete. 

For more details about managing your bank feeds, check out this link: Assign, categorize, edit, and add your downloaded banking transactions.

Let me also add an article for more information about reconciling an account: How to Reconcile an Account in QuickBooks Online? 

Please keep in touch if there's anything else I can do to help you succeed with QuickBooks. I've got your back. Have a great day and keep safe.