Indiana Code Title 27. Insurance § 27-7-12-3

(1) be in writing;

(2) be mailed to the named insured at the last known address of the named insured;

(3) state the effective date of the cancellation;  and

(4) upon request of the named insured, be accompanied by a written explanation of the specific reasons for the cancellation.

(1) ten (10) days before canceling a policy, if the cancellation is for nonpayment of a premium;

(2) twenty (20) days before canceling a policy, if:

(3) ten (10) days before canceling a policy, if the cancellation occurs not more than sixty (60) days after the date of issuance of the policy.