SEO Set up - Site audit, keyword research, meta data

I am working on a fashion/ecom website - a ProcessWire site with Shopify integration.

I am now looking for SEO set-up on the site (it hasn’t been a focus previously as it's driven traffic via social).
FYI - This is not a new website.

I’ve recommended:
A site audit
Keyword research
Implementation recommendations (for back-end Meta initially, and potentially on-page)

We’ll also be setting up PPC campaigns, so we’ll use the keyword search for this too.

For now, it will be the initial SEO set-up, and there's potential for consistent monthly work later down the line.