Complexing Agents are the agents which can form a complex when added to other materials in any solution.
Complexing agents are specially used in cleaning laundry in detergents, in the purification of water ( hardness of water), in every type of cleaning agent, also in solvent extraction methods ( like dissolve like).
Because of its complex formation capability it uses as a cleaning agent. It can form a complex with the impurities and make them static thereby cleaning the solution.
Some examples of complexing agents are phosphates, zeolites, EDTA, etc.