How can I move apps to memory card in Samsung galaxy S3 mini, I am using Android OS version - 4.1.2
App2SD is not working.
Starting with about ICS (Android 4.0), not all devices do support App2SD anymore (for reference, see also: How to move application to SD card in samsung galaxy s duos; the Galaxy S Duos and LG Optimus 4X are two of those devices -- looks like your Galaxy S3 Mini is another candidate, if the "Move to..." option is not there at all).
This is, however, not the fault of Android; it's rather the manufacturers/ROM bakers who decided such: Whatever their support might say (and at least LG support blames Android 4.x not being able to do App2SD), Android 4.x itself can deal fine with App2SD, as plenty of devices prove.
As for a possible alternative, you might want to check move app to sd card, which suggests a.o. Link2SD. Note, however, that root is a pre-condition for this app.