What is .RTFD file extension?
Rich text file similar to an .RTF document, but may contain attachments, such as images, PDFs, fonts, or other files; originally developed for the NeXT operating system and later moved to Mac OS X.
RTFD files are actually "bundles" which contain an .RTF file and the attachments as separate files. In Mac OS X, you can right-click an RTFD file and select "Show Package Contents" to see the files.
You can see a list of software programs here on easyfileopener.org that can open this file type so that you don’t need to search for it on the web. You can then open your file with this extension using a software listed below.