The address on your residence card, the payment methods each provider accepts, how they will contact you, and what to do if you cannot use Japanese.
The residence card address, payment methods, how the provider will contact you, and your building's wiring: what to check before applying for home internet in Japan, based on each provider's official pages.
Two providers take applications in English and other languages (GTN Home Internet and Sakura Fiber Internet). This guide explains what the large providers' English pages cover, and where to look for help if you need it.