Same Database on Subdomain and Primary Domain

Hi Author
Can this plugin work for my question below?

Is it possible to make a website wordpress where in the main domain (domain.com) for the customer (the main domain for sales to the customer ordering the product) and vendor.domain.com for the vendor (I mean this is used for vendor to register as vendor, manage product, entering products, viewing orders etc.).

If it’s possible, how to do it on wordpress (wordpress existing and have database)

Thanks in advance.