I don’t receive any notifications to change the USB settings when I plug my phone into the computer. I have a Moto E4 with Android 7.1.1.
There’s no message in the notification tray of the Moto E after you unlock it (while plugged in)?
No, there isn’t. I used to get a notification but not anymore. And I’ve tried to different computers.
Ok. Does the phone show that it’s charging?
I also do not see the phone on the computer’s File Explorer.
See if this past post (same issue as you) helps
Member Community Moto E4 - Data Transfer not available
Yes, the phone shows that it’s charging.
Have you used this cable before to hook up your phone to your PC? If not, I would recommend using a different cable. Some cables are charge-only cables. Also, try rebooting your phone while it is connected to the PC. Then unlock it, swipe down from the notification tray, and see if the notification appears in the notification tray.