Giving things (物をくれる)
Giving actions (〜てくれる) – someone does something for me/my in-group
Request form (〜てくれる? / 〜てくれない?)
The verb くれる means "to give (to me/my in-group)". It is used when someone gives something to the speaker or to someone the speaker identifies with (family, close friends, etc.). The giver is the subject of the sentence, and the receiver is typically the speaker or someone close to the speaker.
This is one of three key giving/receiving verbs in Japanese, alongside あげる (to give away from the speaker) and もらう (to receive). Choosing the right one depends on who gives, who receives, and whose perspective the sentence takes.
The giver is marked with は or が, and the receiver is marked with に. When the receiver is the speaker, 私に is often omitted.
くれる always implies the action is directed toward the speaker's side. You would not use くれる to describe giving something to an outsider – that would use あげる instead.
When attached to the て-form of another verb, ~てくれる expresses that someone does something for the speaker's benefit. This is one of the most common and important uses of くれる.
Using ~てくれる adds a nuance of gratitude – the speaker appreciates the action. Without it, the sentence would simply state a fact without conveying that feeling.
The honorific equivalent of くれる is くださる, used when the giver is someone of higher status. The て-form request ~てください ("please do ~") actually comes from ~てくださる.
Both くれる and もらう can describe the same event but from different perspectives. With くれる, the giver is the subject; with もらう, the receiver is the subject.
Both sentences describe the same event, but くれる emphasizes what the giver did for the speaker.