When I put bank transaction to account receivable I received a message "Select a Tax to continue." When I Select a Tax I received a message "You cannot track tax on ACC?

I have an idea of what the error message is all about and help you resolve it, hazem.

You'll encounter this error message when you select the Accounts Receivable account and assign a tax code to it. This messes up the accounting, and the system prevents you from doing this. The program will only allow you to track taxes on the expense, checking, and income accounts. However, utilizing the Accounts Payable or Accounts Receivable type of accounts isn't available.

You'll want to use an income account instead of Accounts Receivable when recording the transactions. Please check with your accountant to see which income account is applicable for tracking them. They'll ensure your books are accurate and correct when recording your transactions. 

To get your work done, we can create an invoice or a bill to allocate a VAT code to the transaction. This will add to the appropriate bank account and will help show the tax amount you've paid. I'm also adding here some links about adding and removing the VAT rates or sales taxes on your forms in QBO:

• How do I set up sales GST/VAT rates and use them on forms?
• Applying Sales Tax to Transactions and Sales Forms

Want to see how much you've earned from your clients? There are a variety of reports you can pull up in QuickBooks Online. For example, you can use the Profit and Loss report. Look for an article here. Our help contents have guides and steps on how you can customize and handle your data in reports. 

I'm ready to help you again if you have concerns recording your transactions or with QuickBooks Online. Looking forward to your reply in this thread. You have a good one.