I guess you are asking about the default "services" (apps) which are preinstalled with a vendor flavor Android.
Look in Settings, Apps and uninstall or disable anything you don't need.
On the other hand if you are concerned about Android memory usage, read this old article.
If your concern is security related, install Clueful Privacy Advisor and check the permissions used by the high or medium risk apps. Uninstall any app that requires excessive permissions.
