UK national resident, starting business in USA (I will not promote)

I’m a British guy starting an online Furniture business in the UK and the USA with my partner who is a Chinese national and lives in China. basically my partner is going to handle all of the supply chain i.e. product manufacture quality control supplier management. I will handle everything after that from marketing all the way through to operations and customer delivery. We have both known each other for over 15 years and have around 40 years combined experience in the business. In the UK, we have already created the LTD business as being British I know how to do this in my own country. When it comes to the UsA where I’m not totally sure how things work My Chinese partner also has an existing business in the USA doing the same thing but that is selling product on reseller sites i.e. overstock and eBay . This is a c corp. After chatting to his accountant in the USA, he has advised us to start a C corp because we do have plans to build a big business and hopefully exit one day, and not looking to take any profits out of the business any time soon. At this stage, we have the articles of association and an EiN Number, for the new USA business. The new business will operate from my partners current Warehouse in the USA that already has employees et cetera. One thing I haven’t been able to get clear answer on, is where or how do I become or check im registered part owning the USA business? In the UK, we have companies house and it’s pretty straightforward that you enter your share information and directorship and the company is registered quite quickly. This can be then searched publicly on the company records. I believe the USA doesn’t have to show this information publicly. At the moment the only thing I can see on the articles of association are 100,000 shares and my partner‘s name as the agent there is no information on the regarding the breakdown of the ownership I’m 30% and my partner is 70%. For obvious reasons I’m just trying to make sure that I’m officially registered as owning part of the business. Or is it different in the USA where the shareholders form an agreement with an attorney that breaks down the share information as well as the agreement and this is kept off-line and held between parties?