Even though the 401(k) is the most common retirement account in the United States, not everyone has access to such a plan.
Those who work for governments, schools and non-profit corporations don’t have access to an employer-sponsored 401(k).
If you don’t have access to a 401(k), you can, of course, open an IRA. However, the contribution limits are fairly low, which can be discouraging if you want to contribute a higher amount toward a successful retirement.
The good news is that many hospitals, schools, non-profits (including churches), and governments have their own retirement account offering: The 403(b).