Hi,
When you edit a menu item you have a setting for the text displayed by the browser as title of the tab/window called "browser page title" and a setting for the text displayed by HikaShop at the top of the main content of the page called "Page heading":
monosnap.com/file/zpMjhzRKfKcs2dpndyFoUTVpeJA77e
Also, under the "products/categories options" tab you ave an option "Use the menu name as title":
monosnap.com/file/2CbP4zCpTKsQzjydngqDoidNIODlGc
So if you have that last option activated, the page heading will come from the "page heading" setting of Joomla. If that last option is deactivated, then the page heading will come from the name of the current category.
And the browser page title will come from that "browser page title" if filled in. Otherwise, it will use the page heading/category name selected.