Those are purple hull peas. Nice gift! They're very tasty and keep well when frozen.
The best way is to blanch first. Some people do not blanch, but really it's an important step. Blanching stops enzyme actions which cause loss of flavor, color and texture.
For all types of field peas - including your purple hulls - blanching time is 2 minutes (varies for other vegetables).
To blanch: Measure out enough water to cover peas in a large pot. Bring water to a boil. Once water is boiling add peas. (A metal colander or steaming basket makes it easier)
Return water to a boil, then time the 2 minutes. Immediately remove peas from boiling water and plunge into cold water. Drain peas thoroughly and pack into freezer bags or containers. Then freeze.
Edit: oopppsss...minutes, not mintues