OEM1Stop is intended to provide vehicle repair technicians with easy access to the most up-to-date repair information made available by each of its participating automakers.
There is no registration required for OEM1Stop itself, however, on each participating automaker's page you'll find buttons directing you to that manufacturer's repair information websites. Each of those sites is operated independently by the respective automaker, and each requires its own registration/login process. These sites may also require the purchase of daily/weekly/monthly/annual subscriptions to access repair information.