What Is the Document Number on a Work Permit Location & Purpose Explained

When I first landed my job abroad, staring at that freshly printed work permit felt like holding a golden ticket – until I noticed a string of digits buried in the fine print. The document number, that unassuming alphanumeric code, became my silent companion through every bureaucratic hurdle. It\it\beside the expiry date. US Employment Authorization Documents tuck it discreetly under \while UK Biometric Residence Permits weave it into the machine-readable zone. It\one transposed digit once froze my healthcare access. That string of characters isn\one labeled \and another called \Which is the actual document number for verification purposes?