This is a regular verb. It follows the conjugation pattern of the verb falar.
This verb is more formal in both Brazilian and European Portuguese. In everyday speech, precisar is more commonly used.
Present:
A Ana necessita de mais tempo.
Ana needs more time.
Preterite:
O Miguel necessitou de ajuda ontem.
Miguel needed help yesterday.
Conditional:
A Clara necessitaria de apoio.
Clara would need support.