How to link Customer Estimates and Vendors' Purchase Orders to a Project?

Hello there, userashwathi. 

In QuickBooks, you can directly add the Estimate and Purchase Order to a project. Adding transactions to projects won’t make any changes on how they’re categorised or won't affect your books.  

I'd be happy to walk you through how to achieve this: 

1. Go to Projects.
2. Pick your project.
3. Choose Add to project to create a new transaction.
4. Select Invoice, Receive payment, Expense, Estimate, Purchase order, Time or Bill.
5. Click Save and close.

To learn more about Projects, please refer to these articles:  

• Set up and create projects in QuickBooks Online 
• Projects FAQ 

 However, if you don't see the project feature, make sure you turn it on in the settings.  

1. Click Settings, then select Account and settings.
2. Go to the Advanced tab.
3. Find the Projects section and select Edit. Then turn on button.
4. Press Save and then Done. 

I'm all hands to extend another help. I'll make sure you're all set. Have a great day!