Iowa asked for federal permission to alter major provisions of the Affordable Care Act next year, a proposal that will be closely watched by officials in other states who hope to rewrite parts of the health law as Republican efforts to do so in Congress have stalled.

Iowa’s plan, which state officials said they are already preparing to implement pending federal approval, would go further than proposals that other states have made so far to revamp the health law’s rules. The Iowa setup would offer just one type of insurance...