For indoor cactus & succulents, recommended pot size is 10inch, it may do well in 6 inch pot as well.
Typically an indoor cactus & succulents does not change greatly in size, and you want to avoid excess soil in the pot, which can hold too much water and rot the cactus.
Use a potting soil mix with a little sand; a cactus & suculents likes good drainage. You can mix in a little slow release organic fertilizer, but it is not necessary.
Make sure to pack down the soil around the transplanted plant, and thoroughly water it, to help spur the rooting process in the new soil
While growing, cacti and succulents should be watered at least once a week. Some people water more often than this. During each watering, give the soil a good soaking,
Most cacti and succulents like bright light. A plant that is grown in optimal light conditions will “look normal” , and is more likely to flower than one grown in sub-optimal lighting conditions.