From the FAQs

An official transcript must meet three criteria:

1. It is received from the applicant in an envelope sealed by the issuing institution, or comes directly from the issuing institution via postal mail, electronic mail, or a trusted third party vendor.
2. It bears the institutional seal.
3. It bears the official signature of the institution’s registrar (or recorder of records).

An unofficial transcript is a copy of an official transcript. Examples of documents that are not acceptable as an official transcript include:

• Advising transcripts
• Degree audit from a self-service website
• A copy of a transcript(s) that is prepared and signed by a faculty member, city or government official, or notary public