An authorization letter for HEC is a legal document which gives permission to a third person to go and attest the degrees and transcripts on your behalf. Duly filled-in Application Form and Challan Form or Courier Receipts in case attestation is applied through courier service.An Apostille is a certificate that authenticates the signature of a public official or a notary public on a document for use in another country. Your Name's CNIC number. Your state website should pop up and there should be an application or form you can download. Complete all the required documents indicated in the portal. Once all required documents are marked as complete, submit your registration. You have to show your attested documents from Board and HEC. If you start it from now, it will save your time and money at the time of visa process.