Unlike apples or other fruits, you should not need a blender or other appliance to achieve the consistency your baby needs.
To make avocado baby food, simply peel and take out the pit of a ripe avocado, and mash with a fork. There is no need to cook or warm the avocado mixture at all!
You can add a tiny bit of water, breastmilk, or formula if desired to aid in mashing the puree.