A legal instrument which is executed between two nations and governs cross-border information sharing is known as a:

A memorandum of agreement (MOA) is typically used to outline the general terms of a partnership or project between parties but does not have the formal legal standing or specific provisions for cross-border legal processes that an MLAT provides. As a result, it is not specifically designed for information sharing in legal contexts.

A declaration of understanding is a non-binding document that expresses the intentions or understandings between parties but lacks the legal enforceability and procedural framework necessary for facilitating cross-border information sharing in legal matters. Thus, it does not serve the same function as an MLAT.

A request for urgent information is generally an informal or ad-hoc appeal for data or evidence, rather than a formalized legal instrument. It lacks the structure, obligations, and reciprocal enforcement mechanisms found in a mutual legal assistance treaty.

A memorandum of understanding (MOU) is a more informal agreement than an MLAT and typically outlines cooperative efforts without providing the legal framework necessary for binding obligations regarding information sharing. While it may facilitate collaboration, it does not have the same legal authority as an MLAT.