Make changes to my Wordpress website

Hi

I want to implement a few changes to my wordpress website (sneakerheadsromania.ro) such as:

- a few visual changes to my shop (alignment, and the way it displays in mobile)
- implement a way for visitors to register for a vendor account and to access the Dokan Multivendor Plugin which is already installed or any other multi vendor free plugin with a friendly frontend you recommend.
- add automated affiliate prefixes to the links provided by the Google Custom Search module found in the header
- incorporate a slide in mobile menu that has includes the cart and the Google Custom Search module from the header
- professionalise the look of the cart and checkout pages as part of Woocommerce with something minimal and good looking

In addition to the above a general health check of the website would be appreciate to ensure the code is ok and in good health for Google indexing and SEO.

Thank you
Ranjeet Singh