Direct answer
A corporation acts through authorized people and records, but a job title alone does not answer every signing-authority question. The governing documents, board or stockholder actions where relevant, delegated authority, transaction type, certificate or other evidence, prior conduct, ratification, and apparent-authority issues can all matter. The Supreme Court has stated that an unauthorized officer act does not bind a corporation unless the corporation ratifies it or holds the officer out as authorized to transact on its behalf.
Why this answer is qualified
Authority analysis is both a corporate-record and transaction question. A company considering a contract should identify what the company is committing to, whose approval is required under its records and law, what delegation exists, and whether the signatory's authority can be documented in a form appropriate to the transaction.
Limits of this page
Authority and enforceability questions are fact-specific. This page does not say that a board resolution is always required, that a particular certificate is sufficient, or that a transaction is valid. Material transactions, financing, guarantees, asset disposals, ownership changes, and disputed authority should be separately assessed.
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