Typically, with few exceptions, when you purchase an Android smartphone (or tablet), there are apps on the phone that are pre-installed and cannot be uninstalled (or removed) if you do not need them. Since you cannot uninstall (or remove) these apps, I suggest that you disable them to prevent them from running in the background. To do this (each phone is slightly different), go into the main system settings of the phone and look for the app list or menu. In that menu locate the app you want to disable and look for the option to disable it.
For example, below is an image of the where I disabled the “Gallery” app on my phone. This will save me space on the phone and will save on background memory.