Is zakat obligatory for the owner of a grocery store managed by a partner, where the owner pays twenty thousand US dollars in exchange for a monthly profit ranging from 200 to 300 dollars?

The issue mentioned in the question falls under the zakat of trade goods. Goods prepared for sale inside the shop are to be valued and their zakat paid along with the profits at the end of the hawl (one lunar year). The two partners should pay the zakat proportionate to their share, and its amount is a quarter of a tenth (2.5%). The proof for this is what Abu Dawud narrated from Samura ibn Jundub, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, commanded that sadaqa be taken from what is prepared for sale.