affect / effect
The usual verb of influence versus the usual noun of result, including effect change.
In general use, affect is the verb meaning to influence: The frost affected the crop. Effect is the noun meaning a result: the effect of the frost. Effect is also a verb meaning to bring about: effect a change, effect a settlement. If you mean “have an influence on,” use affect. If you mean “the result,” use effect. If you mean “make it happen,” effect is the verb, and effect change is standard. Do not use affect change unless you mean that change itself was influenced.
Examples
UseThe ruling will affect every tenant.
UseThe ruling had an immediate effect.
UseThe new director effected a change in policy.
AvoidThe ruling will effect every tenant.
AvoidThe ruling had an immediate affect.
Affect as a noun is a technical term in psychology for displayed emotion. Leave that sense to technical writing. Affecting as an adjective means moving or touching (an affecting scene) and is not a substitute for effecting.