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

Requirements
You need this to get it done:

URL
The link you wish to include in your ad (where you would like to send your audience to.)
Headline
A short headline to grab the audience's attention and briefly explain what your ad is about (maximum of 25 characters.)
Image
File format: .jpg/.jpeg or .png
Ratio: 16:9 or 1:1
Minimum width: 254 pixels
Minimum height: 133 pixels
Text
A short description to accompany your ad (maximum of 90 characters.)
Call-to-Action
Decide which type call-to-action button you want on your ad (e.g. Learn More/Contact Us/Download/etc.)
Target Audience
Decide on the audience you want your post to reach (gender, age, location, interests, etc.)
Duration and Budget
Choose how long you want your ad to run and what your daily budget is.
Payment
Choose currency, enter payment details and pay.
Requirements missing or found errors? Report

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

0
Facebook Ads Help Centre - Messenger ads
Information about Messenger ads and how to set them up.
Official
0
Facebook Ads Guide - Image (Messenger Inbox)
Specifications and requirements.
Official
Link missing here or found errors? Improve How-Tos