A vakalatnama is the written instrument by which a party (the principal / vakil-giver) authorizes an advocate (the vakil) to appear and act on their behalf in a specific matter before a court, tribunal, or quasi-judicial forum. In Indian practice, the vakalatnama is the foundational document of every lawyer-client engagement; no advocate can formally represent a party without one on record.
Essential elements: full names and addresses of the executant and the advocate(s); the specific court and case in which the authority is granted; the powers granted (filing pleadings, leading evidence, accepting summons, compromising the matter, receiving money, etc.); the date and place of execution; the principal's signature; acceptance by the advocate; stamp paper and court-fee stamps as required by the applicable state court-fees schedule.
Stamp duty and court fees on vakalatnamas vary by state and court — the single most common reason vakalatnamas are rejected at the filing counter is inadequate stamping. Passport-size photographs of the principal are required in many courts (especially family courts and consumer forums).
A vakalatnama can be revoked by the principal at any time by filing a memo of revocation. A new advocate engaged after revocation files a fresh vakalatnama; the prior advocate typically files a no-objection, though this is courtesy rather than strict requirement.
Multi-advocate vakalatnamas are common for appellate matters; Supreme Court vakalatnamas must be signed by an Advocate-on-Record.