How to Force the Mobile Phone Networks to 2G 3G 4G/LTE on Android

How to force the mobile phone networks to 2g 3g 4g LtE on Android

Input the USsD code *#*#4636#*#* - 

The window will popup, -

Select the option titled Phone Information -

 Set Preferred Network Type -

WCDMA preferred will use both 2G and 3G 

whichever has the better reception -

For 4g/LTE select LTE only. -

For 3g select WCDMA only. - 

For 2g select GSM only.