burn iMovie to dvd
iMac 27″, macOS 12.7
I assume you mean a DVD that can be played in a DVD player.
You will need DVD authoring software like Roxio Toast.
(If your MacOS is older than Mojave, you could use iDVD, if you can find it...)
I haven't used it but I believe that the Burn application has primitive DVD authoring capability. (I too presume you mean a TV DVD player style DVD.) I see that the latest version says it fixed an issue with Tahoe so I am guessing it is relatively up to date in terms of newer operating systems.
How to burn iMovie to DVD
