DOC is the default format used for the documents natively generated by Microsoft Office Word.
Even though it is very popular and it is supported by numerous applications, converting DOC format to TXT will ensure even greater compatibility.
In other words, users can export their DOC files to TXT when they want to make sure their projects can be accessed on any computer, regardless of its installed software.
Converting DOC to TXT will remove all types of formatting from the source file since they are not supported by TXT so only the plain text will be exported.