In school the nuns told us just to say: Jesus, Mary and Joseph.
Satan cannot abide the names of the Holy Family.
You can also say: Guardian Angel in front of me, Guardian Angel behind me, Guardian Angel to the right of me, Guardian Angel to the left of me, Guardian Angel above me, Guardian Angel below me, Guardian Angel all through me, Guardian Angel protect me.
Then too you can say: Archangel Michael in front of me, Archangel Michael behind me, Archangel Michael to the right of me, Archangel Michael to the left of me, Archangel Michael above me, Archangel Michael below me, Archangel Michael all through me, Archangel Michael protect me.
You can say the same for the Blessed Virgin Mary.
You can also just begin praying, saying the Our Father, praying the Rosary, etc. as other posters have said.
Don’t speak to Satan, ask for protection and call your protectors by name.
Satan will fare very poorly against any of these. Satan may have been made very powerful when he was created, but these protectors have a direct hotline to God, and their access to Divine Power is immediate. Satan cannot stand against God.