TIN (Tax identification number)
If I understood correctly, in your country the personal income tax is deducted at source every three months and it is directly transferred to tax authorities by the employer (source https://www.expat.com/en/guide/africa/egypt/14273-tax-in-egypt.html). I would ask the nearest tax office to your place of residence, or your employer. Maybe the number is already on your pay check?
Another hopefully useful link: Ministry of Finance www.mof.gov.eg