The English word “need” is expressed by the words “Notwendigkeit” (f.), “Bedürfnis” (m.), or “Bedarf” (m.) in German:

– “Notwendigkeit”: This is something that is necessary (such as a course of action). The adjective is “notwendig” (“necessary” or “essential”, and “zwingend notwendig” is “mandatory”):
“Es ist unbedingt notwendig dass wir jetzt handeln.” – “It is absolutely essential that we act now.”

– “Bedürfnis”: This word expresses a wish, desire or a longing for something:
“Ich bin frei von materiellen Bedürfnissen.” – “I am free of material needs.”

– “Bedarf”: This word is used for something that is required in a specific situation. It can also mean “demand” (also “Nachfrage” (f.)):
“Es gibt hier viel Bedarf an Fahrrädern.” – “There’s a lot of demand for bicycles here.”
“Es gibt Handlungsbedarf!” – “There’s a need for action!”

The German words for “to need” are “brauchen” and “benötigen”.