Hello everyone.
I want to create an app that uses voice recognition or commands to control LEDs and Servo motors connected to a micro:bit.
Can anyone help me out with getting started?
Welcome Vera.
Yes, there are lots of developers here that will provide advice.
To use voice recognition to command activities you might try HOW TO: Program the native SpeechRecognizer for Continuous Dictation and to do things
Regarding microbit and LEDs try these community topics about using microbit.
They will give you a place to start. 
Alright, Steve.
Thank you very much.