Some files can indeed contain multiple formats within a single file structure, known as container or hybrid files. Instead of holding just one type of data (like plain text in a TXT file), they act as a wrapper bundling different data types together. For instance, a presentation file doesn't just hold text; it integrates slides, images, audio, video, and fonts, each potentially stored internally using distinct encoding standards within the overall container format.

A common example is a Microsoft Word document (.docx). Beyond text formatting, it can internally embed Excel charts, JPEG images, MP3 audio clips, and even link to or embed external video files. Similarly, a PDF (Portable Document Format) file often contains original text elements, raster images (like JPEG), vector graphics, fonts, and sometimes interactive form fields or embedded spreadsheet data from its source application.

These hybrid files offer significant advantages in preserving complex layouts and integrated content for sharing. However, they can introduce compatibility issues if software lacks support for an embedded format, increase file size substantially, and potentially pose security risks as they can disguise malicious payloads within seemingly benign container structures (like malware hidden inside an image within a document). Their design remains crucial for creating rich, multi-media documents.