I’m not sure exactly what you mean by a “wixstore” page so I would assume that what you want to have a filter box for the gallery.
This cannot be done for the built in gallery that comes with the store, however you can create your own gallery by binding a repeater to the store’s products dataset.
One you do that, you can create an input box for your filter and use a “contains” filter in order to filter your dataset:
$w(“#dataset1”).setFilter(wixData.filter().contains(“name”, )