You can renew books from the My Library Account page at https://library.ohio-state.edu/patroninfo/. From this page, you can also check the status of requested items, confirm your campus address, and see any library fines you may have.
Please note some items may have a maximum number of renewals (for example, items obtained via OhioLINK or ILLiad) or may not be able to be renewed at all (course reserve materials).