People move for many reasons, and the types of human migration include:

• external migration: moving to a different state, country, or continent;
• return migration: moving back to where you came from;
• Seasonal migration: moving with each season or in response to labour or climate conditions.

One simple distinction is made between voluntary (based on one's free will and initiative) and forced migrants (often the result of exploitation). Another difference is made between regular and irregular migrants (those who enter or stay in a country without appropriate documentation).