You need to provide proof to someone as soon as possible. Your license may be suspended if you do not provide proof of insurance within the proper time frame. You should follow the directions and provide proof, but you may not want to rely on the mail. It depends on the type of ticket, but you may need to provide proof to the police within a specific time frame. Your license is at risk, if you don't know who to provide proof to and how, call the numbers on the ticket and find out!
Normally if a person can provide proof of insurance coverage on the date of the traffic stop, the prosecutor will dismiss the criminal charge. One way or another, get that proof in. If it were me, I'd bring it in person to make sure it was received and deemed adequate, and to confirm the charge was dismissed. If dismissed, there would be no conviction, no jail time, no fine. If convicted, there would be a conviction, and a fine, and jail if priors, as well as a minimum 30 day loss of drivers license.