CAN I ISSUE SALES INVOICE AND SHOW TO CLIENT THE AMOUNT BEFORE TAX AND AMOUNT AFTER TAX?

Yes, @info-kyriakidesg, you can. Let's go over some details to help you achieve the task in QuickBooks Online (QBO).

Once you've set up your sales tax, QuickBooks Online will automatically calculate the tax amount for you. You can then print or email the invoice with the tax amount included or the other way around. If you want to show the price before tax, all you have to do is uncheck the Tax field and send it to your customer. 

After that, open the same invoice and put a checkmark under the Tax column to show the tax amount. This way, the customer can see both the original amount and the tax amount after sending it to them. See the sample screenshot below for your visual reference.

If you're looking for ways to personalize and add specific info to your sales forms, check out this article for details: Customise invoices, estimates, and sales receipts in QuickBooks Online.

Drop a comment below if you have other questions about managing invoices in QuickBooks. The Community is available 24/7 to lend a hand.