It is better to freeze or can without added sweetener. Saccharin becomes slightly bitter when frozen or heated. Most people sprinkle artificial sweetener on just before eating. If you do add artificial sweetener when canning or freezing, it is better to undersweeten than overdo it. You always can add more later.
Many unresolved questions remain surrounding the use of artificial sweeteners.
If you choose to use them, follow manufacturer's directions on each package. You may can fruit in its own juice or in water, without sweetening. Sugar is not needed to prevent spoilage. Sugar does add sweetness and helps fruit hold its shape. Fruit may be a little softer when canned without sugar.