How can I apply for Honk Kong visit visa from Busan?

You need to apply two seperate ones for visiting HK and Macau through the local Chinese embassy.
For HK, you need to prepare your valid passport, an application form with recent taken photo, round trip tickets to HK and your bank statement with amount of money. For Macau, you may need to need to prepare the same documents and besides you still need to provide a proof of your purpose of visit.