Through the 'Store Categories' module, you can organize your vendors based on custom defined attributes, such as the types of products they sell, store location, service type, etc.
To use this module, it must first of all be enabled in MarketKing -> Modules:

Once this is enabled, you can go to MarketKing -> Settings -> Vendor Capabilities -> Store Management, and choose whether you allow a single category per vendor, or multiple categories:

Configuring Available Categories
Categories can be configured through the site backend, via MarketKing -> Store Categories:

Selecting Categories for Vendors
Both vendors and the site admin can select vendor categories.
The site admin can do it by visiting the vendor profile page and finding the 'Store Categories' tab under 'Vendor Settings':

Vendors can configure store categories by going to their vendor dashboard, to Settings -> Store Categories:

How Categories are Displayed
On the frontend, a category selector will be added to store lists, allowing customers to select the category they're looking for:

Categories are also shown on each vendor's store page under 'Vendor Information' / 'Vendor Details':

Displaying Vendors by Category - Shortcode
To display vendors from specific categories on a page, you can use the following shortcode:
[marketking_vendors_list category=electronics]
Other examples:
[marketking_vendors_list category=electronics,books]
The above will display a list of all vendors from the categories 'Electronics' and 'Books'.