There is a long list of common tools that people use to document test results, be it functional or non-functional.
Word processors: MS Word or Libre Office Word or any other.
Spreadsheets: Excel, Calc, etc
Text Editors: Notepad, Notepad++, Etc
Mind map: xmind, freeplane
Online tools: Zoho Project Manager, Evernote, Google Docs
Test Management Tools: TestLodge, TestLink, TestRail, and so on
Bug Tracking Tools: MantisBT, Redmine and so on.
And any other means of communication people are comfortable with.
There also people who use WordPress for documenting test results.
Basically its up to an individual or a team. First they will have to decide the format in which they would like to document the test results. Once done with that, they can look up the tool that will be a good suit for them and go for it.