Some macOS 10 "High Sierra" users have reported the option to format a drive as APFS is missing from the Disk Utility. Users identified this issue on the Apple Forums and found the solution here.

Step-by-Step

These steps are applicable for our Thunderbolt 3 NVMe SSDs but can be used for other storage devices with little modification. NOTE: This process will erase all data on the external drive leaving it blank, data may not be recoverable.

• In Disk Utility, switch the View option to 'Show All Devices'.
• Select the entry named 'PCIe SSD Media', with 'TBT3_SSD' indented below it, or your specific external drive.
• Click on Erase.
• Change the Scheme to 'GUID Partition Map'. The Format choices will then expand to include several APFS choices.
• Set the Format to 'APFS'.
• Press Erase.

If you have any questions please feel free to contact us at support@plugable.com and we'll be happy to help!