Search or Filter??

Hello
I would like to search in products by weight, or by category, specs etc..
Is this posible with the products search or is this filter??
I just bought Hikashop Essential and it looks like I cant use the Filter function?? but in the comparison it didnt say anything about not being able to filter. Do I need this filter functionality if I want to search products by weight, color category, size etc..??

I just saw in another post that in order to Filter products with custom fields its necesarry to have business version of Hikashop. Unfortunately I have the Essential version. Can I upgrade to Business version if I need to later on easily? without loosing my settings, css and products?

Indeed filters are necessary to do what you want and they are only available with the Business edition.
You can buy an upgrade from Essential to Business on that page: www.hikashop.com/en/component/hikashop/product/cid-3.html

You won't loose your settings or products.
For the CSS, if you edited the CSS via the interface in the Display tab of the configuration, you won't loose it. However, if you directly edited the default file via FTP, it will be overwritten when you update/upgrade so make sure that you do a backup before.