Even if visa applications are now simply submitted to VFS, there is still a chance that the Embassy might ask that you visit them for an interview. If they do, there's no need to come in wearing formal or business wear — casual wear is the best to have as long as you appear respectable and clean. In my case before, I just came to the Belgian Embassy wearing a dress. (Don't go in a revealing dress, of course.) The guys who were there were usually wearing pants and polo. So basically, wear something that makes you feel confident, presentable, and comfortable. The address of the Belgian Embassy in the Philippines is at Multinational Bancorporation Center, 9th floor, Ayala Avenue at Makati (somewhere near PLDT's business center).