I have my own Invoice format. is there a way that we maintain the same format ??? or my only option is to use the templates that QB offers ???

Hello, 

An invoice is one of the main ways that you're able to show your branding to your customers. I can appreciate how important it is for you to be able to use an invoice template that reflects your own style. 
 

You can import custom form styles for invoices and estimates using a Word document. Click here to see how to do it.

With different sample designs, you can import and then add your company info (such as company logo) to highlight your brand. This feature helps reflect your brand identity into your sales forms with less effort and time.

I hope this helps you reach your goal today. If you have any other questions, please don't hesitate to ask. 

Cheers!