To place an ads.txt file for Infolinks.com or any other domain, you should follow these steps:
1. Create a text file and name it "ads.txt".
2. Enter the necessary information for infolinks.com in the ads.txt file according to their instructions.
3. Save this file.
4. Now, you need to upload this file to your website's root directory. For a website running on Xenforo, this is typically the same location your Xenforo's index file is located.
5. Use an FTP client or file manager in your hosting control panel to upload the file.
Once uploaded, you should be able to navigate to "https://yourwebsite.com/ads.txt" in your web browser and see the contents of the file. Keep in mind that "yourwebsite.com" should be replaced with your actual domain name.