英语求助信万能句子

1)如果是写给机构，需要自我介绍

I am Li Hua, a boy of 16 from XX school.

I am Li Hua, a boy of 16 currently studying in XX school.

(2)如果写给亲友或师长，需要寒暄问候

How is it going?

How are things going?

How are you doing these days?

How have you been feeling/doing?

(3)说明写信目的

I am writing to you for some help.