Cookies are popular in Japan and sold at supermarkets and also at confectioneries. Also handmade cookies are made at homes too.
Cookies are common souvenir ar tourist destinations usually related to the tourist destinations or venues. Biscuits are also popular but handmade biscuits are not common.
Not like other Japanese confections, cookies have longer best before dates and suitable for bringing back home when you are traveling around Japan. However, please be aware that cookies are fragile and take care when packing inside your suitcase.