Can I see on the bottom of an ivoice if it has been opened?

Hey there, @dawn70. 

It's great to see you back in the Community! 

I could see how beneficial this could be for your business. However, there isn't a way to see when a customer opens an email/invoice. 

I recommend submitting your feedback to our Product Developers so they can consider this in the near future. Here's how: 

1. Go to the Gear icon in the top right-hand corner. 
2. Press the Feedback option. 
3. Enter your suggestions. 
4. Tap Next to submit your feedback. 

I hope this helps answer your question. If you have any other questions, don't hesitate to ask. Bye for now!