Firstly, you should create a Monkey here https://app.voicemonkey.io/ and set it up as in the instructions from the website. On the Alexa app, you can create a routine When: "Name of Monkey" is pressed Alexa will: Add Action, Alexa Says, Customized, "Add the message you want Alexa says". From: "Your Device"
If
Any incoming phone call missed
This Trigger fires every time you miss a phone call on your Android device.
Then
Trigger Monkey (Routine)
This action will trigger the Monkey you specify including any parameters you set. Use it to trigger Alexa routines!
Discover more time saving integrations for Android Phone Call and Alexa Voice Monkey