I'm using a Samsung J1 with Android 6.0.1 "Marshmallow", and trying to set a Kingston 32 GB Class 4 sd card as the default location for downloading apps. So far, these suggestions are not working:
http/www.tomsguide.com/faq/id-3063648/make-card-default-storage-location-android-marshmallow.html
http/www.tomsguide.com/forum/id-3154053/set-card-default-storage-samsung-galaxy-pls.html
http/www.tomsguide.com/faq/id-3063648/make-card-default-storage-location-android-marshmallow.html
http/www.tomsguide.com/forum/id-3154053/set-card-default-storage-samsung-galaxy-pls.html