First of all I do not know what type of iphone clone is nor the model you refer to.
Second in the iphone 7 clone that I have it is possible to install applications.
But in your case it depends. You have to dare to open it, with one or two guitar-playing reeds. Smoothly, but firmly run the vane around the screen very close to it. If you have a movie, you may have to flee your hand and cut the movie (buy another one and put it on).
Once opened, make sure you have a Micro SDCard slot inside the TF card phone. If so, you're lucky. If not, only by desoldering a block of memory and soldering a larger capacity, resulting in greater risks of operation and expenses.
In case of TF Card it tries several capacities but has to be previously formatted in FAT32 mode. The System will also ask you if you want to format it and start using it. There you go. From that moment all the photos and music you take will go to the TF card and you will be able to install some programs. Type Facebook Lite, Instagrame (different), Twitter (different too). However others that ask to be installed in the ROOT of the mobile phone requires space and there depends on what you intend to do.
Ex of those who want the installation to have access to the mobile phone, root. To be installed you must have space on the Snachat, Instagram, Twitter, iMessenger