How do I copy and paste a line in an estimate ? I have part no that is a group and I want to duplicate it on antoher line

Welcome aboard to the Community space, Sean.

The ability to copy-paste a line item on an estimate is currently not available in QuickBooks Online (QBO). You'll need to manually enter the details every line item you wish to add. 

If you have an Apps menu in your QBO account, you can look for an app from there that lets you copy-paste a line item. If this isn't applicable on your end, please know that we're currently working to have this option available to all global versions of QBO. 

Furthermore, you can also send your feedback to our product development team. This way, they might consider adding the option to copy-paste an item in an estimate in the next update. Here's how.

1. Go to the Gear icon.
2. Select Feedback.
3. Enter your comments or product suggestions. 
4. Then select Next to submit feedback.

Once your customers' accepts their estimate, you can now convert it to an invoice to bill them.

You always have my attention whenever you need help with your estimates or sales form. I'm always here more than happy to back you up!