Is zakat on money obligatory for the owner of the shop, or for each partner in the capital, and what is the amount of zakat that must be paid?

Each partner must pay Zakat on their share of the money if it reaches the nisab, even if it is combined with other Zakat-eligible money they own that has completed its hawl (one lunar year). The partners' money is not combined with each other to complete the nisab. The profit from trade is subject to Zakat as part of the capital, because it is its growth, and Zakat is paid from the profit before it is distributed. Whoever's share reaches the nisab, which is approximately equivalent to 85 grams of gold or 595 grams of silver, must pay one-quarter of one-tenth (2.5%) of the money on which Zakat is due when the Hijri year completes its cycle.