Hello,
If you plan to use WooCommerce default filter widgets (Filter Products by Attribute widget) then you’ll see filters only for those categories where products have these attributes. For example, flowers category https://www.8theme.com/demo/xstore/wedding/product-category/bouquets/ has color http://prntscr.com/i4h1mm but man category https://www.8theme.com/demo/xstore/wedding/product-category/man/ do not have this attribute and that’s why do not have this filter http://prntscr.com/i4h25m but has filter by size instead.
Regards