How to safely home can quality apple sauce using USDA methods.
Put sauce back in pot. If desired, sweeten it with up to 2 tablespoons sugar per litre / quart of sauce you estimate you have.
Bring back to a boil.
Pack hot applesauce into half-litre (US pint) jars or 1 litre (US quart) jars (OR SMALLER.)
If desired, add 1/2 tablespoon bottled lemon juice per half-litre/ US pint, one tablespoon to the litre / quart jars.