The tracking number may come from the USPS, UPS, or another carrier; how scammers access the numbers is unclear, but that's a problem for the carriers to address.

I put tracking on it because I figured that was safe enough, but now I'm quite worried considering the tracking number isn't showing up anything.

The tracking number may come from the USPS, UPS, or another carrier; how scammers access the numbers is unclear, but that's a problem for the carriers to address.

If you search "USPS tracking number format," or the equivalent for any other carrier, you'll see a numeric or alphanumeric format.