Paid by higher taxes.

Canada for example: https://torontosun.com/opinion/columnists/goldstein-the-real-cost-of-free-health-care-in-canada-report

A family of two parents with one child earning $141,749 annually will pay $13,746, while a family with two parents and two children earning $150,177 annually will pay $15,039 through their taxes for health care.