How would I work without a documented QMS? The same way I would with a documented one...
How would I work without a QMS at all? I wouldn't...
I run two companies at present...neither has a "documented" QMS and neither is certified or audited to any published standard (those two sorta go hand in hand).
I've decided what things should be done, how things are to run, I've allocated resources and supplies to tasks, I've used said resources to accomplish the tasks identified, determined the line between "acceptable" and "unacceptable", determined whether results are acceptable or not, etc. ... that's in large part what a QMS is, and what it's for.
Please feel free to use the above to make your question a bit more specific...what are you really trying to ask?