Informal vs. Formal Email

"Dear Ms Riska,

It is our enormous pleasure to invite you to our event..."

We use this format in ____ emails.

"Can you come to my place to help me with the preparation?"

"How's life? Been a while since the last time I met you."

"We would like to ask for your willingness regarding to the invitation as our keynote speaker."

In your opinion, this person uses ____ language in his/her email.

Which one is more polite?

Which picture shows an informal way to open for an email?

If we want to send an email related to job vacancy, we should use ____ language in our email.

"Thanks a lot for your contribution! I wanna know if we can have another event together next year."