Governor Tony Evers declared a public health emergency and issued an emergency order requiring individuals to wear a face covering when indoors and not in private residences effective 12:01 a.m. Saturday, Aug. 1 and will expire on Sept. 28.
This doesn't include private residences - so you don't need to wear one in your own home, but does include all public areas.
It's a lot to unpackage, and there are tons of questions you probably have. Found a nice recap and some common FAQ's can be found HERE.