MIAMI—More than a year after Florida voters approved a constitutional amendment restoring voting rights to an estimated 1.4 million people with felony convictions, widespread confusion surrounds its implementation.

A law aimed at carrying out the amendment has sparked legal battles that remain unresolved, the state has provided little guidance to local elections officials, and some counties are filling the void with inconsistent remedies. Many people with felony records say they aren’t sure how to meet requirements they face...