Which app do you wish to integrate with your QBO?
Yes, you can, @sushama.
You can go to the Apps menu in your QuickBooks Online (QBO) account and link your preferred app from there. I’d be glad to guide you how:
Let me also share this link that you can use for your future reference. This resource can walk you through the steps on how to personalise your invoice and make your brand unique: Customise invoices, estimates, and cash memos in QuickBooks Online.
In case you have any follow-up questions about invoices in QBO, you can always post a reply below. I’d be around to help you out. Have a great day and keep safe!