Avocados can be frozen for later use when you have more ripe fruit than you can use. Avocados are not satisfactorily frozen whole or sliced; they are best frozen as puree for use in salads, sandwiches, and dips.
or lemon juice
Select ripe, softened fruit that yield to gentle pressure. Avoid fruit with dark blemishes on the skin. Wash the fruit, then cut in half, remove the pit and peel. Puree the flesh and add ascorbic acid or lemon juice to prevent discoloration. Add 1/2 teaspoon ascorbic acid or 3 tablespoons lemon juice to each quart of puree or add one tablespoon lemon juice for each 2 pureed avocados. Pack the puree into a rigid container, leaving 1/2 inch of headspace. Seal and label the containers, then put them in the freezer.
I freeze mine in ice cube trays, that way I am not forced to use up more than I need at any given time.
Use the puree within 4 to 5 months