We need the ability to add custom fields on an estimates such as a product color, payment terms or some other detail that can be either optional or mandatory (so the sales rep doesn't forget). That field should also be possible to be added to the estimate that the customer sees. It should also carry over to the work order and invoice with the option to make it visible to the customer.

You can add a "special note" or an 'internal note" but it needs to function more like the work order fields.