It seems now this is a bit of grey area. There were as such rules for IR-for EU-citizens who lived in another country as born in. But untill short ago there were quite different sales channels for IR and ER.

You do NOT need to make all REServ via the app-in fact it is very often rec. here to do it otherwise-f.e. just at DB or via bahn.de. And in fact those white ICE do not require REServ as such-but often it is advisable.

You CAN also buy the old-style paper pass at same prices from DB (you likely have noted by now this is the big german railways), IR at any Reisezenter, Eurail at a few outlets only-airports, the biggest cities. You could just pass y and check there what they say.

The difference is that EU-rl is unlimited anywhere and IR only for 2 days-OUT and IN in homecountry=where you live.

If you live in Germany and have a residence card, then you qualify for Interrail, not Eurail.

If you need to enter country of birth for a reservation, then you're probably trying to book a reservation in Italy. Italian day trains are now better done via ÖBB (using these steps), since that's cheaper (without booking fees) and ÖBB don't need so many personal data.

T

Thx u for reply. That was such a good answer.