You can find several methods on youtube.
I have to do a little guess now with the translation because my device isn't set up in English:
My Samsung asked me to set the media files from the device to the SD card after swiping twice at the top of the screen.
When selecting that, I could choose edit and from there I had to choose the folders I wish to get it on the SD card.
I choose the Android folder.
After this I checked all my apps if they were really working now.
Some did, others asked for a (new) install.
For example my Sygic GPS navigation app asked me for a install when launched.
I had to install all the earlier installed maps again. :-\
So maybe you have to do some extra work after this but it is possible.
Once done, you can be verry happy again and from now on you have plenty of space as your SD card allows.
Sometimes I read about rooting your phone.
If this is ment to be for good:
Better don't run your phone with root priveleges because this will cause safety issues!
If it helps:
My search on the web was with:
"samsung galaxy J500FN apps on sd card"
This lead me to this place and it gave me some youtube results as well.
There are several methods mentioned.
In case my story wasn't clear enough, I will give you some youtube results here to try/to get some inspiration:
Hopefully this is some worthfull information about this bad documented option.