If the watermark is a face that doesn’t match the one in the middle of the bill, it’s a counterfeit. Depending on how old the bill is, it may be an oval or a replica of the face on the bill. If you hold the bill up to the light, you should see a watermark on the right side. Color shifting ink was first added in 1996, so some older bills may not have this feature. Depending on what the denomination is and when it was printed, it may shift from copper to green or green to black. For bills that are $10 and higher, the number in the bottom right corner will appear to change colors if you look at it from a different angle. Counterfeiters will sometimes try to replicate these by printing red and blue lines onto the bills, so compare the texture against another bill - preferably from a bank. Genuine bills will have red and blue threads woven into them. Examine it more closely for further signs of counterfeiting. If you touch a bill and it doesn’t feel right or familiar, it might be a counterfeit. US money has a number of identifying characteristics you can use to check if a bill is genuine. All international money transfer services.
