If you are an individual hobbyist or small repair shop: You legally cannot permanently activate this OS without purchasing a single license through an authorized distributor (e.g., Insight, CDW). A single IoT device license costs roughly $250–$300 USD.
For legitimate testing, search Microsoft Evaluation Center for "Windows 10 IoT Enterprise 2016 LTSB 90-day trial". Windows 10 Iot Enterprise 2016 Ltsb Iso Download
Do not attempt to install this. You will find it incomplete (no store, no modern apps), struggle with driver compatibility, and miss out on years of gaming and productivity improvements. Stick with Windows 10 Pro (which is supported until October 2025) or Windows 11. If you are an individual hobbyist or small