Recently i bought Micromax Unite 2, its a good phone but what problem I am facing is that it comes with internal storage of 4 GB and has external storage and I am using 8GB SD Card.
Under storage it shows free Internal storage of 0.90 GB (free 100 MB), External Storage of 7.47 GB (left 6GB free) and Internal SD card of 1.67 GB (left 1.67 GB free). By default it installs apps on Phone/Internal storage and its getting filled and I am left with only 100 MB and it gets hanged.
What is the difference between Internal SD Card and phone storage?
Can I install all apps on Internal Storage (which is 1.67 GB free)?
For 1) you can think of them like different partitions of a disk. Internal SDCard usually is found at /sdcard (though not always directly mounted there), while internal storage (as referred to) usually goes to /data. More details can be found in our tag-wikis on storage, internal-storage, and file-system.
For 2), most likely not all apps. And if you can do so at all also depends on the Android version used.