When you first started raising kittens, I believe many people would be distressed: Why doesn’t my cat use a litter box? Why does my cat urinate randomly at home? Is there any solution?
Of course, you can train your cat to use the litter box. I hope the following content will help you.

In the first few weeks after birth, mother cats stimulate their kittens to eliminate, and they clean them up afterward. During that time, kittens don’t need litter boxes.
You can start litter training kittens at around 4 weeks of age by offering kitten-friendly litter boxes. This coincides with the time that kittens start weaning.
If you adopt an older kitten or adult cat, you can start litter box training as soon as you bring them home.

• What You Have to Prepare for Your cats?
  1. Choose a Correct Litter Box
  Size: 13 by 9 inches litter box is suitable for kittens. Adult cats or older cats need full-size boxes.
  Style: Uncovered or Covered Litter Boxes.You can give your kitten a choice in the beginning to see what they prefer.
  2. Provide More Than One Litter Box
  It’s better that if the number of cats is N, then the corresponding number of litter boxes is N+1.
  3. Treats and Toys
  Train your cats by rewards.
• How to Train a Kitten?

1. First, you can show your kitten the boxes at a fixed location, making sure the boxes will not be moved and let your kitten sniff them.
2. Then, you can place your kitten in the litter box. They may instinctively start pawing at the litter or even using the litter box. If they don’t, run your fingers through the clean litter to demonstrate the pawing action.When they begin to use the litter box, you can praise them and give them a treat or a toy.Make your cat remember this behavior through repeated training.
3. Finnaly, keep the litter box clean. For clumping litter, scoop the box out at least once a day, refill as needed to maintain the proper depth, and do a full replacement at least every three weeks (more often if you have multiple cats). For non-clumping, scoop solid waste daily and toss out all of the litter to replace at least once a week (again, more often if you have multiple cats). Regularly clean out the box with fragrance-free soap and water as well.
4. Attention: Never punish your cat for not using the litter box. Punishment will make your cat feel scared and cause excessive stress! If at first you don’t succeed, keeping trying! Many pet parents may become discouraged by an accident or two, but remember: Cats naturally gravitate toward doing their business in a litter box.

Sources:

1. https://www.hillspet.com/cat-care/training/how-to-litter-box-train-a-kitten
2. https://www.petmd.com/cat/training/evr_ct_how-to-litter-train-a-cat
3. https://www.petfinder.com/cats/cat-behavior-and-training/cat-litterbox-training/
4. https://be.chewy.com/how-to-get-a-kitten-to-use-the-litter-box/