Certificates of coverage are the forms that SSA and the German authorities issue to
workers who would otherwise have to pay Social Security taxes to both countries on
the same earnings. A certificate of coverage issued by one country serves as proof
that the worker named on the certificate is:
subject to the laws of the country issuing the certificate and
exempt from Social Security coverage and contributions on the same earnings in the
Certificates of coverage should be requested by the employer in cases of employment
or the worker in cases of self-employment.