Before entering the USCIS biometrics center with your USCIS appointment notice, be sure to leave your cell phone or any digital camera in the car or with a friend. Cameras and phones are not allowed in the USCIS offices.
Once your appointment gets underway, you will be asked to fill out a form. The form will ask for some personal information, and you will also need to indicate what form you filed that requires the biometrics.
Next, your fingerprints will be taken. Most USCIS offices still use ink to take fingerprints — however, more offices are switching to electronic fingerprinting.