Is it possible to ask the travel agency to apply the visa on my behalf?

I'm an Indonesian married to Malaysian and currently staying in Malaysia. I'd like to travel to China with my friends next month. I have few questions to ask.
A) Is it possible to ask the travel agency to apply the visa on my behalf?
B) If i dont go with tour agency, how to apply the visa by myself, any extra documents i need to bring/submit to China embassy.
C)If i apply for single entry can i visit to Macao as well?
Thanks.