Online platforms are a great place to search. Websites like Amazon, which sells both physical and digital copies of books, might have it. Also, some e - book platforms like Kobo or Barnes & Noble's Nook could have the 'infinite magic light novel' available for purchase or even for free if it's in the public domain or on a special offer.
Another option is to check out libraries. They have a wide range of books, including light novels. You can ask the librarian if they have the 'infinite magic light novel' in their collection or if they can order it for you. Some libraries also have e - lending services, so you can borrow the digital version if available.
You can try looking for it in local bookstores. They often have a section dedicated to light novels. If it's a popular one, it should be there.