Create a sub-domain on an existing WP site with lead form

Description

I need a website designer who specialsies in WP. We have an existing website and need to create a subdomain, which has about 8-9 pages, and can accept form data. There will need to be a good quality database which is easy to access with a CMS in the backend. I can share more details about the project. This will be a multi-year project. Therefore, it's best to include some maintenance activity also.