Add photos, movies, and files in TextEdit on Mac
You can place photos, movies, and files (such as another text file, a spreadsheet, or an app) in rich text documents. When you add a file, it appears as an icon in your document.
In the TextEdit app on your Mac, do any of the following:
Drag a photo, movie, or file to your document from the Finder.
Choose Edit > Attach Files, select the photo, movie, or file, then click Open.
To open a file you attached, double-click the file icon or drag the icon out of the document to save it. Adding a file in your document increases the size of the document by the size of the file.