Clarification on domestic helpers in Korea

Hi there, 

I'm looking for some clarification.

1) Can filipinos apply to be domestic workers in Korea? Is it legal? Which visa does that fall under?

2) Do they need to have an employer first before applying for visa? 

3) If entering Korea on a tourist visa and then working illegally as a helper what are the implications?

4) What is the pay like for filipinos as a domestic helper. 

Just for the record, I'm not filipino and I'm not looking for a job. But my current helper has informed me that she wants break her contract to apply for a job in Korea as a helper. As her current employer i need to do due diligence and find out the implcations and try and explain it to her, 

Appreciate any advice possible.