Which button is used to add new elements or features within a project?

The Insert button is the correct choice for adding new elements or features within a project. This button is designed to facilitate the enhancement and enrichment of your project by allowing users to include various elements, such as clips, audio tracks, text titles, effects, and other media components. It streamlines the workflow by providing a straightforward way to introduce new content or features directly into the timeline or the workspace where the project is being developed.

In digital video editing, the ability to insert new elements is crucial for building a cohesive narrative and ensuring that your project meets the creative vision you have. The Insert button typically opens up a range of options from which users can select what specific elements they wish to add, making it an essential tool for any editor.

The other options do not serve the function of adding new elements. The Play button is utilized for playback of the project. The Stop button halts playback or any ongoing process. The Delete button, as the name suggests, is intended for removing elements from the project rather than adding new content. Thus, focusing on the Insert button's role highlights its importance in the project development process.