Read the pitch deck that buzzy startup Devoted Health used to reach a $1.8 billion valuation before it signed up a single customer

Devoted Health wants to change the way the U.S. takes care of its senior citizens, and it has big plans in its first five years to do just that.

The startup, which has been gathering lots of buzz in the last year, was founded to sell private health insurance plans to U.S. seniors, a market that is growing rapidly as Baby...