Apple - APFS on external drive missing from Disk Utility

Disk Utility will only offer APFS if Partition Map is "GUID Partition Map".

If the Partition Map is "Master Boot Record" APFS is not an option (and neither is encrypted HFS).

Edit:

The problem is, that DiskUtil only shows you the Volumes on already partitioned disks. Just select View -> Show all devices. Now instead of the Volume select the device you want to partition and APFS and GUID will be offered.

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I was able to get the APFS and GUID scheme option by deleting the MBR

1. Open a Terminal
2. Find out which disk is your target: diskutil list
3. Unmount the disk: diskutil umountDisk /dev/disk# with # being the number of the drive you determined in step 1 (e.g. /dev/disk2)
4. Delete the MBR: dd if=/dev/zero of=/dev/disk# bs=512 count=1

If you open DiskUtil now you will be offered APFS

Disclaimer

• Be aware that you are deleting all partitions from the drive
• Be careful when selecting the disk

If it is not giving you the option for APFS formats, then you are likely trying to format only the logical volume within the container.

To show the container and physical disk in disk utility usually you have to change the view option to "show all devices" from "show only volumes",

Now you can select and format the container as you want.