Mut'a marriage agreement can be recited by the woman and man after they agree on the Mahr and period of the marriage. She should tell him in Arabic : Zawwajtoka Nafsi 'Alal Mahr Al-Ma'loom Lil Modesto Ma'loomah. (Means : I agree to be your Muta wife for the known Mahr and period). The man should reply her saying : Qabilt or Qabilt al Tazweej Linafsi 'Alal Mahril Na'loom Lil Muddatil Ma'loomah. (Meas: I accept the marriage for the known Mahr and period.)
Wassalam.