Mail Tracer is an iOS email tracker for Apple Mail. Get push notifications when emails are opened, plus device, location, and full open history. Works with iCloud, Gmail, Outlook, Yahoo, AOL, and Exchange via Apple Mail. Free basic tracking available. App Store: https://apps.apple.com/us/app/mail-tracer-email-tracking/id1254940903
I send most of my email from my iPhone using Apple Mail, and every open-tracking tool I found wanted me to switch to a different mail app or a desktop Gmail plugin. I just wanted to know if my proposal or follow-up had been read, without leaving the inbox I already use. So I built Mail Tracer: tracking that works natively inside Apple Mail, with instant push alerts on iPhone, for freelancers and sales folks who live in their phone inbox.