You don't need to hold a legal license to become a solar installer in every state. However, many states require specific training as a prerequisite for this role. Plus, the requirements might be different for commercial or residential installations.
If you reside in a Tri-state area, you can become licensed and certified in surrounding states. We recommend you give yourself time to get licensed and establish yourself in your region. Note that licensing can be expensive up-front but pays off in the long run.
State websites declare different laws and regulations for solar installer licensing.