I would like to make changes in SEO and mainly on the Google search results and the content of these results,
The modifications or rather the additions that interest me are on the one hand:
The addition of product information, when one of my products appears on Google I would like to have price and availability information below the "meta description"
(I add a screenshot to make its more explicit)
In a second time I would like to add a picture near of some products and some collections
Its free and it can add it should be able to add the schema markup you want.
I guess you have to hire a web developer to integrate the Rich Snippet code. This rich snippet code helps to feed all product information to search engine bots. It is easy to fetch your product info in Organic result when someone search your product.
No, you can install that app yourself from inside the Shopify app store.
Yes, here's a link to a guide, jump to "Step 3" https://www.nerddigital.com/shopify-seo-tips/
Feel free to reach out to me on nerddigital.com in case you need more help.
Give that app a try, its free no need to get a developer.
I would only recommend getting a developer if the app doesn't work with your theme, but give it a try first.
Feel free to reach out to me at nerddigital.com if you need more help or just want to have me take a look at this for you.