The only scholarship provided to prospective students before their arrival in Japan is the government scholarship provided by the Ministry of Education, Culture, Sports, Science and Technology or the MEXT scholarship for short. The ministry's official link suggests to "contact Japanese embassies, consulates in your countries, or institutions of higher education which you wish to enroll." Most Japan embassy web pages have a section on studying in Japan where you may access more information.

https://www.mext.go.jp/a_menu/koutou/ryugaku/boshu/1330944.htm
Source: Ministry of Education, Culture, Sports, Science and Technology website

After your arrival in Japan under the student visa, there will be many scholarships you can apply. Some scholarships can be applied individually while most are applied through the university. International students may receive help during the application process.

https://www.jpss.jp/en/scholarship/
Source: JAPAN STUDY SUPPORT, The Asian Students Cultural Association