Hand over money, business cards, or gifts with both hands — or with your right hand while your left lightly touches your right forearm.
Using one hand, especially the left, can read as careless or rude in formal contexts. Two hands signal sincerity and respect, particularly when dealing with elders or someone of higher status.
This applies to handing back change at shops too. Cashiers often place money in your hand with both hands; mirror the gesture when you pay. It is a tiny effort that locals notice immediately.