Unfortunately you can't put apps on an sd card. The sd card can only hold data, like pictures and some game data.
With phones that only have 8 GBS internal storage, you have to be creative and clean it out regularly with a restore to factory. A lot of junk builds up and fills up and slows down the phone.
use apps like DropBox and Google drive to store pictures and video
there is a way to minimize or uninstall some Bloatware if you have apps that are unneeded.