Hi,
Date]

[NAME, COMPANY AND ADDRESS, ex.
Tom Atkinson
COMANY Inc.
14 Edith Street,
Hackney West,
ZIP POST CODE]

Dear [NAME, ex. Tom Atkinson],

This is to inform you that [Name of your new company]
is now open and is located at [street, city, state, zip address].

Our store offers a complete and diverse line of [Description
of what your company specializes in].

Enclosed, for your review, is a brochure of our company

We hope that you will come and visit us soon.

Yours very truly,