第一日返工,點寫e.mail介紹自己呢?

Dear all,
This is Heida, your new colleague(shipping clerk), nice to meet you and work with you! If anything I can help in future, pls feel free to contact me at extension xxx or email xxx anytime.

Have a nice day,
Heida

看看好不好:-
Good morning, colleagues.
This is XXX and I am a new guy for the compnay as a shipping clerk. my extension is XXX and I hope that we can have a good cooperation.

Dear (name): I am (your name), I join your firm am because of (reason), everybody many advises
親愛的(名字)：
我是(你的名)，我加入貴公司是因為(原因)，大家多多指教