How do I join copper to PVC pipe?

You solder a threaded adapter to the copper pipe, then screw on a PVC adapter, one is male threaded adapter, the other female. It matters not which is which.

Yes, it does matter which end is male and which one is female. In this application, plastic should be male, copper should be female. In other words, you always screw weaker material into more solid material.

Another option is as follows: Install "SharkBite" coupling. They are Home-Owner friendly. Both pipes just snap in. No soldering or glue is necessary. Home Depot sells them.

Smearcase: Bingo ! Glad to be of service !

( Some claim "Shark Bite" fittings will eventually replace soldering... )

Here is the picture of the sharkbite coupling9894