Here is a diagram of bike parts and their names.
https://guides.wiggle.co.uk/bike-jargon-buster-guide Take a look and try to tell us where the grease is coming from (headset, hub, etc.) There are greased bearings in the headset and hub that occasionally ooze grease and usually nothing to worry about but these parts do need maintenance every so often and you'll need to learn to disassemble/assemble them. If you can post a photo of where you found the grease it would be very helpful and we can go from there.