Within Ormoc City, tricycles are the main transport for short distances and are cheap and plentiful. Habal-habal (motorcycle taxis) are faster for slightly longer routes within the city. Both can be negotiated for a fare before you get on.
For Lake Danao National Park, you will need to hire a jeepney or take a habal-habal from the city — ask at your hotel or at the market for the going rate. The road is paved most of the way but becomes rougher near the park entrance.