Notices should always be in writing; they should state, in precise terms, their object, and be signed by the proper person or his authorized Lawyer, be dated, and addressed to the person to be affected by them. There can be several types of notices like for example consumer complaint legal notice, constructive notice, legal notice to the department concerned if his/her promotion is not granted. It is basically a concept describing a requirement that a party be aware of legal process affecting their rights, obligations or duties. Legal notice is an important document before proceeding to any court of law for your grievance.
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