Action Details
Requirements and how-to articles for Google My Business's action:

Write a post about a promotional sale or offer from your business.

You need this to get it done:

Offer Title
Write an eye-catching name for your offer (maximum of 58 characters.)
Offer Details
Tell the user about your offer (maximum of 1500 characters.)
Start/End Dates and Times
Set the start date and time and the end date and time for your offer.
Photos should be simple, direct, in-focus and well-lit, with bright, vibrant colours.
File format: .jpg/.png
Minimum resolution: 400 x 300 pixels
Note: You can use either a photo or a video, but not both.
File format: .avi/.mp4/.mov/.flv/.wmv/.mpg/.m4v/.mkv/.m2ts/.mts
Maximum file size: 100MB
Note: You can use either a video or a photo, but not both.
URL (if applicable)
The URL the customer must visit to redeem the offer.
Coupon Code (if applicable)
The coupon code needed to redeem the offer.
Terms and Conditions (optional)
You can add terms and conditions for your offer.
Requirements missing or found errors? Report

How-To Articles
A list of useful links for you:

Google My Business Help - Post on Google
Official guide to making business posts on Google.
Link missing here or found errors? Improve How-Tos