Praise be to Allaah.
Women can wear rings on any finger. Imaam al-Nawawi (may Allaah have mercy on him) said: “The Muslims are agreed that the Sunnah is for men to wear rings on their little fingers, but as for women, they may wear rings on all their fingers.” (Sharh al-Nawawi ‘ala Muslim; ‘Awn al-Ma’bood, 11/286). And Allaah knows best.
Sheikh Muhammed Salih Al-Munajjid