The MoSCoW method is a prioritization technique used to decide which requirements to complete first. It divides requirements into four categories:

Must have (M):
- These are critical requirements that must be included in the solution. Without them, the product cannot function or meet user needs.
- Example: For a messaging app, a "Must have" might be the ability to send and receive messages.
Should have (S):
- These are important but not vital requirements. They are high-priority items that should be included if possible, but the product can still function without them.
- Example: For the same messaging app, a "Should have" might be message read receipts.
Could have (C):
- These are desirable but not necessary features. They are lower priority and often considered nice-to-have.
- Example: For the messaging app, a "Could have" might be the ability to customize the chat background.
Won't have (W) (this time):
- These are features that are agreed upon as the least critical or out of scope for the current project or release. They might be considered for future iterations.
- Example: For the messaging app, a "Won't have" might be integration with third-party apps for the initial release.