How do I check if my client has viewed the estimate/invoice that I’ve sent him?

If you’ve enabled the customer portal for your business in Zoho Invoice and configured it for your customers, they can view their transactions with you by logging into the portal. This includes viewing and accepting/declining estimates as well as viewing invoices.

The client viewed estimates and invoices can be filtered for separate viewing,

• Go to the estimate or invoice tab under Sales on the home page of Zoho Invoice.
• Click on the drop down next to All estimates or All Invoices on the top left hand corner, and select Client-viewed.
• You can now see only the estimates/invoices viewed by the client.

Alternatively, you can simply click on the particular estimate or invoice and check if it has been viewed by the client. A tiny eye icon on the right corner of the estimate/invoice page accompanying the words Viewed suggests that the client has viewed it.