For MOTO E 2015 GSM USE [boost/Sprint/Verizon Works Fine][PreActivated]
1. Power on the device with the GSM SIM card in the SIM card slot 2. Connect to WiFi and complete Google Sign-In 3. Go to the Play Store and search "Network" download the first app (A white circle with a black phone in it) (This will allow us access to the advance radio options) 4. Open the "Network" shortcut 5. Change the radio mode from "CDMA/LTE PRL" to "GSM/LTE Auto" 6. Open up the settings app, go to the mobile networks panel, select "Prefered Network Mode" and change it to "4G" 7. Input the appropriate APNs for your specific carrier 8 (Optional). Disable all Verizon apps through settings or Titanium Backup. The only thing I couldnt solve was how to remove the "SIM Card is from unknown source " or "SIM Card is not from Verizon Wireless" error in the status bar permanently, but thats just an annoyance, and causes no usability decrease.
Source and Credit :-XDA Developers