Shift to a hard gear and pedal standing. If the click is worse, and from the BB area, it's the spindle to bearing interface. Most people only lightly grease the spindle. Quiet for a few rides then the noise returns. A more thorough fix is a thin film of loctite on the spindle where the bearings sit. I use loctite blue but I'm sure there's a better formula for non permanent gap fill.
If the noise is around the headset and louder during hard efforts:
thin film of waterproof grease on all the headset parts, headtube bearing seats and spacers. Careful check for squareness of the cone spacer to the stem's bottom. Set the headset tension with the expander, tighten stem. Ride. Loosen stem bolts, retension, retighten stem.