iTunes
I have a iPhone 5c and I would like to know how to remove an iTunes account from it
Sign out of the iTunes store.
There isn't really any such thing as an iTunes account so it is hard to be specific. Do you mean unsubscribe from Apple Music?
Manage your Apple Music membership - Apple Support - https://support.apple.com/HT204939 - "Learn how to change from an Individual membership to a Family membership, turn off automatic renewal, or join Apple Music later." Turn off autorenewal and your membership will finish at the end of the current subscription period.