The Buddha is only recorded as ordaining one woman, I think, his step-mother, Pajāpati Gotamī. When asked about the other women, he gave allowance for the bhikkhus to ordain them:
“anujānāmi, bhikkhave, bhikkhūhi bhikkhuniyo upasampādetun”ti.
This is all detailed in the Vinaya, Culavagga 10.