Well you can move photos, music, videos, etc., over, but not apps. You would need to be running at least Android "Marshmallow" to be able to set the SD card as "Internal" rather than the standard "External" which allows for apps to run off the card.
Moving the photos, videos, etc., over will free up a lot of space though, so that would help.
I would also suggest clearing out data in the apps you run all the time (just make sure it isn't something you need) by going into "Setting"... "Apps"... and clicking on individual apps and tapping either "Clear Cache" or "Clear Data".
IMPORTANT NOTE: Do not do this with apps that were already on the phone. You can cause major problems for the phone. I would stick to doing it only with apps you...