Tell the organization if ubuntu is free and if any documents are needed for inspection bodies
Ubuntu is just a collection of programs (packages) that come with their own licenses (GPL, MIT, etc.) for each package.
At the moment, the policy of Ubuntu developers when choosing packages that will be distributed with Ubuntu is such that it will NOT include packages with "non-free" licenses.
Under the "not free" licenses, as regards their financial part, one must understand that they prohibit the use of programs for commercial purposes and may still require payment for the acquisition or use of the program.
In Ubuntu, however, such programs are not popular, because they give preference to their "free" counterparts, which do not require payment (although this is not prohibited, for example, in the same GPL licenses) for their purchase or use.
Therefore, ABV LLC can download Ubuntu for free, for example, from the official website ubuntu.com and use it for commercial purposes, within the framework of the law, of course.
Documents for inspections
As a rule, the only document that is available for a particular program from Ubuntu is its license, the text of which, if necessary, you can print out.
For more details on software authentication in offices, I suggest that you familiarize yourself with this article .