There are two words in the Vedic tradition which can be translated as donation, these are: danam and dakshina.
Danam, the donation, as mentioned in the Taittiriya Upanishad, is
offered to a worthwhile cause or person, which protects and values Dharma, - justice, what one should do in one's various roles, and what is correct. Making a donation blesses us with punyam, merit, which makes us worthy of protection in unexpected moments, when we have no power over a given situation.

But there are several factors that must be present to make that which is given to someone a danam. Danam must be offered with sincere respect to the one receiving it, without any internal or external form of disrespect. It must be given with a full heart, without the feeling that something was sacrificed. It should be given with modesty, without the attitude of being superior to the receiver. It should be given with the concern that the person accepts and feels blessed by it. And finally, it should be given with an understanding of what the person needs, with friendship and satisfaction so that the other person doesn't feel they owe something.

Dakshina is what is offered to someone performing a ritual on your behalf, or to a teacher. The person who receives it must have a good attitude and know what they are doing, they must have an understanding. The result will come, from the ritual and the teaching, as the proper offering is given. The dakshina is offered on a plate with the appropriate money and a flower and fruit, or by some other established method.
The person, with humility offers the best possible and says: "dattam mayaa". This was given by me with respect and devotion, please accept it.