Chrome extensions start with a manifest.json file, defining metadata like name and scripts.Manifest V3 will become the standard for Chrome extensions starting from June 2025.Options for Chrome extension implementation include popup, new tab, sidebar, and embedding widget.Popup extensions display a small interface when the extension icon is clicked.New tab extensions open a full tab when activated, suitable for more complex interactions.Sidebar extensions provide a vertical panel next to the current webpage for persistent tools.Embedding widgets allow small interactive elements to be added to web pages through content scripts.Choose the implementation based on your extension's needs and user experience goals.Manifest V3 requires careful permissions handling and rigorous testing for security compliance.Consider the specific requirements of your extension to select the most appropriate implementation method.