How to Attach Screenshot to service appt message

[Monroematt]

I would like to attach a screenshot of an error message about the chargeport latch not engaging. The message is on my mobile app. I took a screenshot, but am having difficulty attaching the screen shot to the message feature of the mobile app. I select the camera icon, which brings me to the screenshot I want to select, but I can't see how to attach it to the message. How do I do this?