I sent a letter, but there is no email application installed on her mobile phone. Does the system have a letter notification by default? Can she see it?

This can definitely tell you: she can't see.

There are three conditions for a mobile phone to receive a letter notification: 1. The mobile phone is equipped with email application, which can be used normally. 2. The letter prompt setting for this application has been turned on. 3. The network where the mobile phone is located is unobstructed.

First of all, her mobile phone does not have this application installed, which does not meet the most important conditions, so she will not receive a letter notice. Your mobile phone may receive a feedback prompt that the email has been sent, but only if you turn this prompt on.

If there is something urgent, you can choose WeChat or even SMS notification.

I hope I can help you!