This sample letter of inquiry is a good base from which to start, the italic lettering is where you have to insert your own information.

[Date]
[Address]
[Phone Number]
[Employer's Name and Title]
[Employer's Address]

Dear [Name of hiring manager]

I have been informed of a job opportunity as [specific position or area you are applying for] by [name of referrer]. I am very interested in such a position because [qualifications or related work & interests].

I am currently employed at [name of organisation] as [title of position].

or

I have just graduated from [name of academic organisation]. [Achievements related to the position] [Note: Read Writing about achievements guide]

I look forward to discussing this job opportunity further and how I can contribute to the success of [name of organisation].

Sincerely, [sign your name ] [type your name ]

Modify the Sample Letter of Inquiry, it is a good idea to add your own flavour.