Can you save documents on a DVD?

Yes. Any file format can be stored on a DVD disc.

However, you can't just save or write to a DVD. The supported method is to create a DVD image on your hard drive and burn the whole image to a blank DVD.Programs are available to do this.They can be purchased but free programs to do this are also available. Later versions of Windows may also include the ability to burn to a DVD.

There are also rewriteable DVD drives with rewriteable DVD media. They also need to be burned the same way but it can be erased and burned again.

Some CD/DVD burning software also claims to be able to format the rewriteable media in such a way that additional document files can be written to it afterward.