All available settings of Search you can find in Theme Options > Header > Search.
If you need to have something more, try to use third-party search plugins that include this.
Please note that we don’t give guaranty for full theme compatibility with all 3-rd party plugins.
Unfortunately i cannot find the option to search by brand. It has only SKU.
Can you please recommend a third party search plugin (compatible with the theme)?
If I install a search plugin will the search icon remain in the header or I have to insert the search box from a different place?
Built-in search includes search by posts, pages, products (description, title, SKU) by default. There is no option to search by brand, tags etc. We did not test search plugins with our theme and especially search by built-in brand option, so, we can’t recommend anything, unfortunately. Actually, I suppose if you want to search bu built-in brand then you will need additionally customize either theme or plugin. You can contact Codeable or WPkraken teams to submit customization request and get the quote.
If you use third-party search plugin you will need to replace our search by the plugin search field. If you choose theme customization then you don’t need to replace search.