How do I upload ads.txt to the main directory of my site?

[BluRayHiDef]

I'm using xenForo 2.2.10 and my site is hosted by xenForo. How do I upload ads.txt to the root level domain of my site? Google requires me to do this in order for advertisements to function properly. Where is the option to upload such a file in the control panel?
How do I upload ads.txt to the main directory of my site?

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