Follow the below steps to implement ads.txt. You may need to contact your Hosting company for further instructions.
If you are using Wordpress as CMS, you may use an ads.txt add-on.
1. Create a new ".txt"-file and copy-paste the rows from Holid.se/ads.txt (our latest version of ads.txt)
2. Save the file as "ads.txt" and/or make sure that the file name is "ads.txt"
3. Upload this to the root of your domain, so that it is accessible on YourDomain.com/ads.txt