Compare the phase of the voltages across components of a series RLC circuit
Suppose we have a series RLC circuit with equal impedances


The impedance of the capacitor cannot have the same impedance as the inductor - it can have the same magnitude of impedance but the impedance polarity is negative compared to an inductor.

So, assuming that is what you meant, those two impedances will cancel out leaving only the resistance (loss) across the power supply. This resistor determines the current that flows. That current is in phase with the supply voltage.

Across the capacitor and across the inductor are voltages that are 90 degrees to the current flow: -

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