The subject of making or giving offerings is important to Kanaka Maoli and is a marker of respect when one is visiting a wahipana (sacred place) such as a heiau. The giving of an offering goes deep into Hawaiian mythology and within the Hawaiian epic of the Kumulipo, nature emerges before the gods. The Gods are then given birth and they in turn give birth to humanity. While in the Judeo-Christian traditions, G-d gives man dominion over the world. In the Hawaiian world view, man is given birth by the Gods as an offering to nature. That relationship is important to understanding Hawaiian offerings.
In ancient Hawaiʻi, there were several types of offerings—more than 30 types that I know of. The most common type is the hoʻokupu. This has become a general term used to mean all types of offerings but that was not the case even 150 years ago. Hoʻokupu in former days were formal offerings made by the common people to a king or chief normally during an important occasion and was a way of honoring both the chief and the Gods themselves. The last hoʻokupu of that sort happened on Queen Liliʻuokalaniʻs birthday in 1917. Nowadays every offering is called a hoʻokupu but originally the accepting party would be a chief who acts in his/her role as a descendant of the Gods and required a specific ceremony. That is why the root word “kupu” in this case means ancestral spirit or supernatural being because a chief or king accepts such an offering on behalf of the Gods.
What we nowadays think of as a hoʻokupu would have been more commonly called ʻālana, which are more informal types of offerings. There are actually several types of ʻālana. The ʻālana aloha was a daily offering made by Native Hawaiians to their family ancestors, the Gods and the peace of the world similar in many aspects as the canang sari of the Balinese. These could be given on shrines, to special trees, to special rocks, or to the ocean or mountain itself. The uluʻālana was a form of offering made by a priest to the Gods normally at a shrine or temple. Kahukahu were food offerings made to the Gods or to departed ancestors. These food offerings would be specially prepared near the spot or eaten at the spot with the smoke (the aka or essence) or steam being given to the Gods or ancestors and the meat and fruits consumed by the participants. (Hawaiians did not leave meat, fruits or fish on altars). Hua mua were types of offerings made by giving the first plucked fruit of the season or first fish back to the ground or sea as an offering.
The type of offerings that travelers (including Hawaiians visiting a new place) should be aware of are the type called ʻālana komo. Although ʻālana komo are confused often called hoʻokupu, they are different. Hoʻokupu have a formal structure. ʻĀlana komo was offerings made as a mark of respect upon entering a sacred site and does not require a formal ceremony. Specific Hawaiian families have their own traditions on the ʻālana komo when they visit a place but normally it would be related to their location (i.e. a specialty crop or rock of their region), a flower or fern, and red sea salt.
Tourists sometimes thinking that they are paying respect will leave pineapples, coins, and candies on Hawaiian altars. This should be discouraged. Hawaiians did not like to leave rotting things on altars. Appropriate offerings by tourists would be flowers particularly flowers that are red, white, or yellow. Red, white, and yellow are general colors used favored by a number of male and female Gods. Normally such offerings would be wrapped in green ti leaf (green representing nature and the imagery of nature and Pō is throwback to the Kumulipo). If one can not wrap it, itʻs fine as well. If one is going to leave a lei, ask the vendor if the string is biodegradable. Many lei vendors have begun to use biodegradable string or some recycled material. I know of people who simply buy ti leaf leis as offerings in order to not have to worry about biodegradable string and ti leaf wrappings. If using a ti leaf lei as an offering, the lei should be placed on an altar or platform horizontally. Putting a ti leaf lei around a kiʻi (temple image) or lopping the ti leaf lei should be avoided. A closed ti leaf lei was normally in ancient times was normally only worn during a period of mourning. So the ti leaf lei should be left open.
This advice also goes with visiting Hawaiian statues. There is a tendency for people to leave leis on the tongue of the lei niho palaoa of the statue of Queen Liliʻuokalani. That should be avoided. If one is unsure of where to leave an offering at a statue, the food of the statue of the person itself is the best place. Some statues like that of Queen Liliʻuokalani tend to have an extended hand and one will see Hawaiians offering leis on that hand. That is appropriate as well.