Search the library eBook catalog: Publishers don't provide digital versions of traditional textbooks to libraries, but some course materials are not traditional textbooks. You may find the text you need in the catalog if it is popular non-fiction, a short story without commentary, or a scholarly monograph.
Ask your professor: If you need a section or chapter of your textbook as a stop-gap until you can get a copy for yourself, your course instructor may be able to work with the library to have a portion scanned for personal use.
Check your local public library:
Reach out the the publisher: Although most publishers have stopped providing emergency access as they did in the latter half of Spring 2020, there are some publishers who are accepting requests from individual students for help getting textbooks. Publisher information for textbooks can be found on the Barnes & Noble page for your book.