To answer the original question:
This answer uses the exFat file system type instead of Fat32.
See this link for instructions about how to create an exFAT USB drive, from within Linux, that will show up in macOS, Linux and Windows.
blkid -o list and
df -h to work out the device block of your Linux attached USB drive (e.g: /dev/sdb)
Install exfat utilities in Linux (e.g: Ubuntu in this case)
sudo apt update && sudo apt install exfat-fuse exfat-utils
Use fdisk to partition the USB drive.
sudo fdisk /dev/sdb
Create a new partition table and clear all current partition data.
o at the prompt for a
MBR partition table or
g for a
GUID Partition Table (GPT).
Create a new partition (In this case ONE partition for the whole drive).
n. It will ask for some values which you can simply press enter for the default values.
Change the partition Type
When you run
fdisk in Linux OS a new partition is given the partition
Linux by default. macOS will not recognise that. To change the partition Type flag to
exFat we have to type in the command
t. Fdisk will now ask for a number indicating the flag you want to set. We want number
HPFS/NTFS/exfat. (You can see all the flags by typing
Save the Partition table information.
Write the settings to the USB drive by typing the command
w in fdisk.
Create a filesystem (exFat).
Now we have a partition but no filesystem yet so make one like this:
sudo mkfs.exfat /dev/sdb1
Now data you save to this drive will be available in macOS, Windows and Linux