Ads.txt is an initiative by the advertising industry to help curb counterfeit ad inventory by allowing content owners the ability to specify who is allowed to sell their advertisements. You can read more about it at the official page on IAB Tech Lab.
You can use this plugin to control the contents of your ads.txt file, even when using our Community In The Cloud services where you would otherwise be unable to upload the appropriate txt file needed. Note that on some hosting environments you may need to first create the ads.txt file using FTP and chmod it to allow the file to be written (e.g. 0777). This is not necessary with our Community In The Cloud offerings.