McDonald's does offer health insurance to employees. The coverage is offered through a company called the BCS Insurance Group, and may differ somewhat from one state to the next as far as coverage and availability are concerned. Keep in mind, also, that not all McDonald's stores are owned by corporate offices and the exact benefits packages and how they can be attained may be different at Franchise units.
In most cases, eligibility for health insurance through McDonald's begins after you have been employed for 90 days. Eligibility may also be limited to employees who work a minimum number of hours. To find out the exact details for a particular location, the best suggestion is to contact that store's manager and ask them directly about health insurance and how it is handled through the store.
One thing about health insurance purchased through McDonald's that you should be aware of is that the company does not typically pay any portion of the costs, which could range anywhere from around $730 to $1700 a year. At the lower end, your maximum benefits may only be around $2000, and at the upper end you could be limited to between $10,000 and $12,000 annually.
Additionally, McDonald's has indicated that it may opt out of the health insurance program once certain aspects of the Affordable Care Act go into effect. The argument presented and currently being debated is whether the insurer is capable of meeting the 80/20 rule, which requires insurance companies to spend a minimum of 80% of the premiums the collect on health care for their insured members. While this is subject to change as the deadline for implementing the 80/20 rules draws closer, BCS has indicated that it would be unable to continue providing health services under that provision of the law. What this means is that it would be best to verify they are still offering insurance before you put in your application if health insurance is a determining factor in the job.