There is also the verb "devoir" + verb in the infinitive form.
Ex : je dois terminer ce projet. (I have to finish this project).
"Devoir" = must. It's a regular verb so you need to conjugate it like a normal verb.
"Falloir" (mentioned above) il also a verb but it's only conjugated in the 3rd person singular "il faut que..." = it is needed that...
Ps "I need to do... ", "I have to do..." and "I must do..." are not as clean cut in French. They are almost interchangeable.