U.S. citizens living in a foreign country for at least 330 days of a 12-month period are not required to get health insurance coverage for that 12-month period. If you're uninsured and living abroad under this definition, you qualify for a health insurance exemption. This means you don’t have to pay the fee that other uninsured people must pay.
If your income is below the filing threshold for your filing status, you are automatically exempt from any penalty.
More information here: https://turbotax.intuit.com/tax-tools/tax-tips/Health-Care/Are-You-Exempt-From-Health-Care-Coverage-...