NDAs come in two main forms: one-way (one party shares, the other receives) and mutual (both parties share). Standard provisions: definition of confidential information, permitted purpose, restrictions on use and onward disclosure, exclusions (information already public, independently developed, etc.), duration (typically 2-5 years), and remedies (injunctive relief plus damages). NDAs are routine in M&A (signed before sharing DD information), employment (employees, contractors), and commercial relationships (early-stage discussions).