Besides my manager who do I need to distribute test documentation to? E.g. master test plan and master test report.
Do I need to send the product owner/business representative, who is unfamiliar with the software testing process, a copy of those?
There's so much testing documentation you could produce, your audience will vary massively... test plans, strategies, summaries, risk assessments, defect reports, etc. Not everyone needs to see everything.
Define your project team and ask them how much information they want, or how much they need.
For example, at my current client, only the Project Manager is interested in weekly progress reports in UAT, but the Test Manager wants daily progress reports.
Everywhere is different, unfortunately. There's no real standard!
Whomever needs it. There is no standard that you have to follow.
I always hate it if I get information I do not need. How do you figure out if people need something? Either ask them, or leave them out until they ask for it.
I would place any test documentation on a central place (e.g. a wiki) where everyone can reach it. Inform everyone once that they can find it there.