How to forcedly use 4g network on smartphone?

It's quite simple if you want to use 4g network forcedly on your smartphone. But many peoples want to know how can they use a stable 4g connection, Even on poor 4g network. Because phone finds strong network, when phone gets a 3g strong network then it lost 4g network. So now you can use 4g network forcedly now on your smartphone. 

 
Follow my instruction : Dial *#*#4636#*#* on your dial pad.

Force lte support

Select phone information.

Now select LTE only.

Many peoples use force LTE apps lol you don't need these apps.