This article covers 

How to add custom comments to an invoice?

Can I add notes to already generated invoices?

Summary

In Chargebee, invoice notes can be added at multiple levels.

• Site-wide - to all invoices under the site

• Customer-specific - to all invoices specific to a customer

• Subscription-specific - to all invoices under a subscription

• Invoice-specific - to individual invoices
  
  

Invoice notes will be added when the invoice is generated for the 1st time. It is not possible to add a note to an Invoice that is already generated or not in the current term. 

Tip: You can regenerate the invoice, for recently updated notes to populate in the current invoice.

• To add notes at the site level
  
  Go to Chargebee Dashboard,
         > Settings 

> Configure Chargebee 
> Invoices, credit notes, and quotes
> Click Invoices tab
> Navigate to Invoice Notes
> Click Add
> Enter the notes you wish to display on all your future invoices (This will be displayed in the PDF Invoices. You can also add HTML content here.)
> Click Apply changes

• To add notes to a customer or a specific invoice
  
  Go to Chargebee Dashboard
        > Subscriptions/Customers
        > Click to open the subscription/customer-specific record to which you want to add a note
        > Scroll down to the heading Invoice Note and click Add Note
  
  

Related articles and Documentation

How can I introduce a break in the invoice notes and make them appear in multiple lines?