Set phrases for opening paragraph

I am writing to you in connection with..

I am writing with regard to / in regard to / with reference to.

I am writing to ask if you could informal me about..

I was interested in your advertisement in..

I would appreciate some further information about..

Referring to your advertisement published in.

I am writing to give you some information about.

I am writing in reply to your letter.

In reply to your letter concerning..

With reference to your letter of.

Set phrases for closing pparagraph

I would be very grateful if you would / could reply as soon as possible.

Thanking you for your time assistance.

I would like to thank you in advance.

I look forward to your reply at your earliest convenience.

I look forward to hearing from you.

I hope this information will be of some help to you.

I would be happy to supply you with any further information..

If you need further information, do not hesitate to contact me.