A SR-50 is a form used by a person to provide proof of current insurance to the Indiana Bureau of Motor Vehicles (BMV). This form shows the Bureau both the beginning and end dates of the current policy. It is just one of the types of forms that the BMV notes that Indiana motorists may be required to submit if they have been involved in accidents or who have received citations for traffic offenses.
For example the IN BMV notes that if a person is not insured at the time of a violation, they may be subject to a one year suspension of their driving privileges, owe a reinstatement fee of between $150 to $300 and will be required to have an Affidavit of Current Insurance, or SR-50 form, filled out and returned to the BMV by their insurance company.
The Indiana government site has the Affidavit of Current Insurance "SR-50" form online if you wish to look it over.
If you are required to obtain certain insurance coverages to reinstate your driver's license then the court involved or the BMV should be able to inform you exactly which auto insurance coverages these are and if you will have to do so even if you do not own a car. Likely you will have to get auto insurance to reinstate your driver's license, even if you do not own a car, but only the BMV can tell you for certain since they will be able to discuss your specific situation with you.
If there is a car in your household in which you could place insurance or be added to the policy of then you will need to do so in order to receive the SR50 and get your license reinstated. If there is no car for you to place insurance on then you can obtain a non-owners policy. Once you figure out the policy you need you can then get this car insurance coverage and inform your insurance agent that you will need a SR-50 form filled out.