Formatting USB memory in Ubuntu 18.04
In a terminal type 'sudo lsblk' then note the NAME of the USB.
Then type '
Then type '
sudo dd if=/dev/zero of=/dev/sda bs=4M iflag=nocache oflag=direct' to overwrite it with zeroes in blocks of 4M. Check with lsblk above again, and note the NAME of the USB (without numeric ending, eg sdb NOT sdb1).
Once done, type '
sudo parted /dev/sdb mklabel msdos' ie NAME of USB. It may complain and ask to reboot. Oblige. Once up, re-type.
Then call utility 'Disk' using [Window] key. It will bring up all the volumes (hard disk, USB) on the left pane. Select the right volume (USB). Then on the right pane tap [+] (near the two gears icon) to create partition with a chosen format (FAT32, preferably). Initially its Partition type is Linux.
It has a sliding option of 'Erase data or not' [while partitioning]. I choose 'Erase' which takes time [20' for 32 GB]. Eventually, its Partition type is FAT32.
To mount it for the first time, tap the triangle icon at the bottom of the volume on the right pane.