A file format shows how its inside is arranged.
A picture, a text file, and a PDF can carry the same words, but a program does not read them the same way.
An ending such as .pdf or .jpg is a hint.
Changing the ending by hand does not convert the file.
Naming a .jpg as .pdf does not turn the picture into a document.
To convert it, open the file in a tool that does that job.
A file format tells a program how to read the file. It defines how the data inside is arranged, including byte order, structure, and encoding. The format is inherent to the file’s content, not its name.
People need to understand a file format when they want to open, edit, or transfer the file with different software. The file extension is only a hint; changing it does not alter the underlying format.
No. Changing the extension only changes the file’s name; the internal format remains the same.
The file itself defines the format; programs interpret it according to the format’s rules.
Open the file with a conversion tool and save it in the desired new format, which rewrites the internal structure.
