授受表現N4
あげる／さしあげる
to give (to someone) / to give (humbly to a superior)
Structure
N + を + あげる / さしあげる（相手：に）
Explanation
あげる means the speaker (or in-group) gives something to others, marked with に. For superiors use the humble さしあげる (e.g., 友達に本をあげる; 先生にお土産をさしあげる).
Examples
友達の誕生日に、本をあげました。
I gave my friend a book for his birthday.
先生にお礼のプレゼントをさしあげました。
I gave the teacher a thank-you present.
Note
あげる is not used when giving to oneself (use もらう). さしあげる is for superiors. Note the extended use 〜てあげる (doing something for someone).