All apps are installed in Internal Storage these days. Ealier version of Android (circa 2.2) had App2SD which allowed some parts of the app to be moved to the SD card, however this was only because they partitioned internal storage so the space for apps was very limited.

Assuming your phone didn't originally come with an early version of android and has a reasonable amount of internal storage, I'd be surprised if you'd filled internal storage with apps alone: I expect you still have lots of other stuff there.

Try getting a file manager from the Play Store (I use a free one called File Manager) and using it to locate and move things to the SD card. I'd start with bigger file types like videos, MP3s and images.

You could also trying clearing caches and deleting/moving the contents of /Download and any other locations apps used to put downloaded stuff.

 

Go to the Apps section of ur settings and move the apps to ur external sd card by swiping to the right.