Tax Residency governs treaty entitlement and allocation of taxing rights, with credits, information exchange, and anti abuse limits. Tax treaties allocate taxing jurisdiction by reference to domestic residency rules and treaty articles: residence (determined under each State's domestic law) primarily governs treaty entitlement; allocation of taxing rights grants residence States primary taxation of worldwide income while source States retain limited or conditional rights (e.g., business profits taxed only with a permanent establishment). Treaties cannot create new domestic tax charges (non aggravation). Relief from double taxation is provided by credit or exemption methods (full, limited, or exemption with progression). Competent authorities may exchange foreseeably relevant information, and limitation on benefits clauses guard against treaty shopping.