A scribe is a person who writes the exam on behalf of a candidate who cannot write due to a disability.
PwD candidates who are eligible can request a scribe as per the rules in the official notification.
The scribe is usually required to be from a different academic discipline than the candidate.
Candidates using a scribe generally also get compensatory (extra) time in the exam.
You must declare the scribe requirement in the application form and carry the required undertaking or certificate to the exam centre.