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

Single Billboard
paid action
Very popular size in Poland. Performs well in both brand and direct-response advertising campaigns. Currently only available in Poland. Suitable for text ads and display ads.

Requirements
You need this to get it done:

Single Billboard
You can create a responsive display ad, or upload a display ad. You can also choose to copy existing ads.
You can upload image ads as .gif, .jpg and .png
You can upload AMPHTML ads as a .zip containing 1 HTML document and up to 39 media assets.
Maximum file size: 150KB
Dimensions: 750 x 100 pixels
Requirements missing or found errors? Report

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

0
Google AdSense Help - Guide to Ad Sizes
List of different ad sizes and how well each one performs.
Official
Link missing here or found errors? Improve How-Tos