The purpose of an Elastic Job is to execute a T-SQL script that is scheduled or executed ad-hoc against a group of Azure SQL databases. Targets can be in different SQL Database servers, subscriptions, and/or regions. This blog post is quite long and heavy (code wise) so grab a coffee and follow through.
The architecture you could follow is shown below.
All of the code is in Powershell and Arun talks us through it.