Ajax Product Search is another advanced add-on for Woostify. This responsive live search engine, which will boost your user experience by providing a user-friendly ajax powered search form. You can filter the results with the title and SKU. Keyword autocomplete also included.
Go to Woostify Options to install and activate Ajax WooCommerce Search extension
If you want to enable Search by Category, you can go to Settings of the extension then enable it, and enable other options below
Then check the result on the frontend