How can i see where other people such as my friends unlock my phone with face id so i can remove them instead of resetting my whole face id?

According to Secure your iPhone or iPad with Face ID... "If there is an alternate appearance that you don’t want to keep or if you believe someone may have added an alternate appearance on your device without your permission, you can reset Face ID, then set it up again.

1. Go to Settings  > Face ID & Passcode, then tap Reset Face ID.
2. See the above task to set up Face ID again."

Maybe someone else will have a better answer, but here is what I found in this link:

https://appletoolbox.com/multiple-face-id-users-ios-12/#Can_I_Delete_or_Change_An_Alternate_Appearance_for_Face_ID

“Once you enter an alternate appearance, there’s no option to delete it! Instead, you need to Reset Face ID to change your alternate appearance. Unfortunately, that also means you must re-enter all Face IDs! When you tap Reset Face ID, your device removes and deletes all your Face ID data–including your original Face ID and your alternate appearance.”

My question is how are your friends managing to add their faces to your ID? It cannot be done without your passcode. You may want to change that.

Set a passcode on iPhone - Apple Support