Yes, I assisted my father with a book project on his family history.
You will want to scan the recipe cards using either a scanner or an iPhone with a scanner app. These will save the cards as JPEG or TIFF, and you should scan them at 300dpi or higher.
You can then use a program like Pages to create an attractive recipe book. Add your text and add the scans of the cards. When the book is complete, you can save it as a PDF or EPUB file and send it to the relatives.
If the completed book is a large PDF, I’d suggest storing it on a cloud storage service like iCloud, Dropbox, OneDrive, et al and “share” the link in your email to your relatives.
