In legal practice, to affix means to attach, apply or place something (such as a seal, signature, notice, label or exhibit) to a document, instrument or property to authenticate it, execute it, or give statutory or court‑ordered notice. The word is not generally defined in one statute, but is used across legislation, court rules and case law, which often specify what must be affixed, by whom, where and how.Common uses include: affixing a company’s common seal to a deed or share certificate (method usually set by the company’s articles; seals are optional in England and Wales, Scotland and Northern Ireland, but procedures remain common in Ireland); affixing statutory notices in a conspicuous place on land or premises (e.g. planning, licensing, housing or enforcement regimes), where strict compliance can be a condition of valid service; and affixing exhibits to affidavits or witness statements with appropriate marking and certification. Historic references include affixing adhesive revenue stamps to instruments.In electronic execution and sealing, “affixed” can describe attaching or logically associating an electronic signature or e‑seal to data under the UK’s retained eIDAS framework and the EU eIDAS Regulation in Ireland.Practically, verify the governing provision or articles: defective affixing may invalidate execution or notice. Usage is broadly consistent across the UK and Ireland.