How to shift storage of new apps to SDcard ?

[Android Central Question]

I have a Samsung Galaxy Grand Prime (not + version). I want to install new apps but my phone has an internal memory of 8GB (which covers up very quickly).
I have a 64GB sdcard but I cant install my new apps on the basis of storage in the sdcard. They always consume the phone space.
I searched a lot on the internet. All I found was nothing else but a dead end talking about rooting your phone. And now, it's amazing that I have fallen into a new trouble.
i.e. on tapping developer options in my settings, I receive the pop-up that this device is already rooted but on using root-related apps, I get to know that my phone is still not rooted.
I'M STUCK IN THE MIDDLE !!
My android version is updated.
Somebody please help me out of these two problems. It'll be much obliged.
Thank you !

 

[Rukbat]

I have a 64GB sdcard but I cant install my new apps on the basis of storage in the sdcard. They always consume the phone space.

Android downloads to, and installs to, internal storage. There's nothing you can do about that.

I searched a lot on the internet. All I found was nothing else but a dead end talking about rooting your phone.

Rooting doesn't allow you to install apps on the SD card (it just uses a bit of internal storage).

And now, it's amazing that I have fallen into a new trouble.
i.e. on tapping developer options in my settings, I receive the pop-up that this device is already rooted

Already rooted, or "You're already a developer"? One has nothing to do with the other. "You're already a developer" just means that you already turned the developer menu on. That has nothing to do with rooting or with not having enough internal storage for the apps you want.

but on using root-related apps, I get to know that my phone is still not rooted.

Probably because you haven't rooted it.

About all you can do about the space is use an app like Apk Extractor. Keep just those apps you need installed, and keep the apk files for the others on the card. When you need an app that's on the card, uninstall one that's on the phone and install the one you need. (An 8GB phone is too small for 2008. Even a 32GB phone is getting a bit small now.) Rooting the phone won't give you more space. (And moving apps to the SD card, with apps that can do that, is a really bad idea. The card will go bad - they don't last forever. Then you lose your apps and the data for some of them.