How do you burn .iso files to DVDs in Mojave?

Here you go: Burn CDs and DVDs on Mac - Apple Support

If you have quesrions after reading that, let us know.

Follow these steps:

1 - insert a blank DVD disc in the optical drive (in Mojave blank discs don't show in the finder - a bug).

2 - mount the iso/dmg image on the Desktop.

3 - Control (right) - click on the mounted disk image and select "Burn XXXX to disc" from the contextual menu. For video DVDs its best to burn at the slowest speed possible.

My only guess would be to use hdiutil in Terminal. hdiutil Man Page - macOS - SS64.com

While the above is still useful, the reason I couldn't see the burn options was that my external optical drive wasn't recognized when attached to a hub. I connected it directly and was able to see the burn options in the contextual menu.

The problem with Mojave is that a blank DVD to be burned may not appear on your desktop for you to open. If this is happening to you, then the burn procedure gets more more complicated. First open the Mac OS Disk Utility to see that the blank DVD is recognized. If so, then you can write to it even though it is not on your desktop. To do that, create a burn folder on your desktop from the File Menu of the Finder. Give it a name xxxxx and load it up with the files you want to want write. The burn button in the upper right of your burn folder may not be active. If so, you must go to the gear icon of the burn folder to select the option Burn "xxxxx" to Disc... from the pulldown menu. At this point, Mojave figures out where you want to write even though nothing is on your desktop. We should hope that this workaround will be unnecessary soon.

Thanks guys I got it to work and burned some photos onto a cd using the Create and use a burn folder on Mac.