How to buy municipal bonds
https://www.thestreet.com/how-to/how-to-buy-municipal-bonds-15127751--very Little Chance of Default
By and large, state, city and local municipal bond issues are for necessary projects vital to a state, city or locality. These bond issues go toward public works projects which are either taxed or generate fees, thus guaranteeing a steady stream of revenues toward repayment of the bond's principal and interest from the government issuer. - -
You can can read many books about bonds at Google books and learn how to reaseaand buy bonds