thanksgiving are christmas cactus
I have two cactus and they have not bloomed in several years. What can I do to make them bloom?
Plants will bloom, or grow, or do whatever they're supposed to do, when they have what they need to be healthy and strong. (Not unlike people.) If yours aren't flowering, they're missing something in their environment; it's up to you to figure out what. Often this is a process of elimination - change one thing at a time, and see how they plant responds.
First, here are the basics of blooming Christmas cactus: https://www.gardeningknowhow.com/ornamental/cacti-succulents/christmas-cactus/how-to-make-a-christmas-cactus-bloom.htm
The most likely situation when plants don't flower is either too little light, or too much nitrogen. Try putting you plants into a higher light situation. Also, try using a phosphorous fertilizer (high middle number,) or just work some bone meal into the soil for a more organic approach.
Have you repotted recently? If not, you might try that, using a good-draining potting mix. (I like to use a 50-50 mix of cactus soil and perlite.) Here are some tips on that process: https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm