Go to the Effects panel and search for "Neat Video." It will typically be under Video Effects > Neat Video > Reduce Noise . How to Use Neat Video in Premiere Pro

Neat Video offers a Free Demo version (which has limitations like watermarks and frame size caps) and a Pro version.

Neat Video is a digital filter designed specifically to reduce visible noise and grain in video footage. Unlike the native noise reduction tools found in many editing suites, Neat Video uses advanced mathematical algorithms to distinguish between fine detail and unwanted noise. Key Features: