If you have software that is used "to achieve conformity to product requirements, prevent product mix-up and ensure orderly handling of product" then you need to define what the infrastructure requirements are for the software. (ERPs and ECN systems jump immediately to mind). Infrastructure would include, I believe, the server, any physical access requirements for the server (key access, etc.), any environmental aspects (cooling for the server), and so on. Probably power (UPS) should be considered. Might also need to consider server capacity (is there sufficient capacity to not crash the system if everyone tries to access it). Probably also need to consider the client systems as well.
Now the question about documentation is still somewhat fuzzy in my mind. I currently maintain an inventory of software applications to enable documentation of consideration of / requirements for validation. I may just add to this. I don't necessarily like the idea, though, of separating that from the other infrastructure requirements.