A parametric EQ provides surgical control over frequency shaping. The Q parameter controls bandwidth: high Q (narrow) for surgical fixes (removing a specific resonance); low Q (wide) for broad tonal shaping. Most mixing EQs are parametric — they offer far more precision than graphic EQs (which have fixed frequencies and bandwidths).
The FabFilter Pro-Q is the modern standard for parametric EQ with its intuitive interface and spectrum analyzer overlay. Every DAW includes a capable stock parametric EQ. Semi-parametric EQs have fixed Q (bandwidth) while fully parametric EQs allow Q adjustment — the latter is preferred for precision work.