Hi, I am currently learning & honoring the Morrigan myself. I have found this small prayer:
Prayer for Morrigan
“Morrigan goddess, I need you,
support me, guide me,
let your strength and your power show me the way to succeed.
I am ready for it, I am ready for you.
Blessed be.”
I started with this website The Morrigan for a jump-off to how to learn more & the books suggested are well written.
There is also this post with a meditation for the Morrigan & in the replies there is one for Macha