What form do I need to register for healthcare in the country where I live if I am insured elsewhere?
You will need a so called S1 form.
The S1 form allows you to register for healthcare if you live in an EU country, Iceland, Liechtenstein, Norway or Switzerland but you are insured in a different one of these countries.
This is typically the case of pensioners retiring abroad. It can also be useful for members of the family of migrant workers who have stayed in their country of origin but are now covered by the social security insurance of the country where their family member now works.
It corresponds to the old E106, E109, E120 and E121 forms.