> For the complete documentation index, see [llms.txt](https://help.payorcrm.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.payorcrm.com/manual-collections/track-invoice-opens-email-opens.md). # Track Invoice opens/Email opens The app allows you to track customer email activity in two ways: 1. **Customer email open tracking (Step 5)** - This feature tracks the last date the customer opened the email. 2. **Invoice PDF link tracking (Step 3)** - This feature tracks the last date on which the customer opened the invoice PDF using the 'view PDF' link in the email reminders. Together, these features can help you track whether the customers are receiving and viewing the invoice reminders.