Whether you can or can't move installed apps to the external MicroSD card depends on the version of Android you're running. What version do you have?
Pre-installed apps can't be moved to the external MicroSD card unless the device is rooted.
And if you are rooted and have moved some pre-installed apps to the external MicroSD card that will probably interfere with the device's proper functioning.
And if you are rooted and have moved some user-installed apps to the external MicroSD card that will probably interfere with those apps' proper functioning.
Also, rooting voids all warranties. So that's not recommended with (relatively) new devices.