Providing Eccomerce platform for stores

I have seen this idea that I want to implement. Where I will have multi-sites subdomain or directories. The service that will be provided is online stores platform using subdomain/subdirectories from the main domain
Where my clients/users can have and create their online stores with name they chose as independent online store.
for example.
Main domain => service provider (www.123.com)
client A will come to create online store as sub-directory with name they chose.
https://www.123.com/Store-A
Another client B will come to create online store as sub-directory with name they chose.
https://www.123.com/Store-B
and so on, so each sub-directory will be as independent store.

What tools and plugins will make this scenario is possible?