All players competing on the Seniors Circuit require an IPIN membership.
IPIN stands for “International Player Identification Number”.
Players who register for IPIN membership will receive their own unique IPIN, which will remain the same throughout their career playing in ITF tournaments.
Click here to login or register for ipin
These documents may help you
1) How to register for your ipin (german).
2) How to extend your membership (german).
3) How to sign in for a tournament (english).