Formal and Informal E-mail Expressions in Englis ...

"Hi..., Hi there..., Morning/Afternoon/Evening..., Hello again..." are formal or informal expressions?

"Rgds, Cheers, Bye for now, See you soon" are formal and informal expressions?

"I am writing to thank you for all your help" is a formal or informal expression?

"Yours sincerely, Yours faithfully, Yours truly" are formal or informal expressions?

"A social invitation to a friend at your workplace" is a formal or informal e-mail?

"Dear Mr Piper, Dear Sir or Madam" are formal or informal expressions?

"Regards, With best wishes, With many thanks and best wishes" are formal or informal expressions?

"A job application" is a formal or informal e-mail?

"I look forward to seeing you next week" is a formal or informal expression?

"Many thanks for your help" is a formal or informal expression?