i read on a website that phione can ont evolve into manaphy but can she produce manphy eggs?
Phione has not, can not, and will not ever produce a Manaphy Egg. The opposite is true, however; breeding a Manaphy with a Ditto will result in a Phione egg. Maybe you heard it wrong?
No, Phione cannot produce Manaphy eggs, Phione can only produce Phion eggs.
Hope this helps!