Use GParted

see the video

You can install it

• from Ubuntu Software Center or

• on the command-line:

  sudo apt install gparted
  

Use the command line

see the video

1. To show the USB drive among all storage partitions and volumes on your computer use:

   lsblk
   

   You can also use:

   df
   

2. Suppose it may be /dev/sdy1. Unmount it with:

   sudo umount /dev/sdy1
   

3. To format drive with the FAT32 file system format:

   sudo mkfs.vfat -F 32 /dev/sdy1
   

   To set a file system label for your pen drive in the process:

   sudo mkfs.vfat -F 32 -n 'name_for_your_pendrive' /dev/sdy1
   

   You must include the -F 32 part to specify the FAT size, it is not 32 by default in ubuntu 19.10. For more info see man mkfs.fat.

The Command-Line Way

In case you can't get your device formatted from the GUI, try this way.

1. Open the Terminal (Ctrl+Alt+T)

2. List your block storage devices by issuing the command lsblk
   Then identify your pen drive by it's SIZE. In my case its /dev/sdb

3. Erase everything in the pen drive (This step is Optional):

   sudo dd status=progress if=/dev/zero of=/dev/sdb bs=4k && sync  
   

   Replace /dev/sdb with your corresponding device.

   Type very carefully this name or your may end up erasing one of your other disks. This will take some time. (option status=progress is not mandatory but provide you some feedback)

   It will pretend to be stuck. Just be patient.

   for example:

   dd if=/dev/zero of=/dev/sdb bs=4k && sync
   dd: error writing '/dev/sdb': No space left on device
   
   1984257+0 records in
   1984256+0 records out
   8127512576 bytes (8.1 GB) copied, 1236.37 s, 6.6 MB/s
   

4. Make a new partition table in the device:

   sudo fdisk /dev/sdb
   

   Then press letter o to create a new empty DOS partition table.

5. Make a new partition:

   • Press letter n to add a new partition. You will be prompted for the size of the partition. Making a primary partition when prompted, if you are not sure.

   • Then press letter w to write table to disk and exit.

6. Format your new partition.

   • See your new partition label with the command lsblk
     In my case it is /dev/sdb1. Once again pay attention to this name as there will not be any protection to prevent you to erase an other disk.

   • Issue the command below to format the new volume:

     sudo mkfs.vfat /dev/sdb1  
     

     Please replace /dev/sdb1 with your corresponding device.

   • Eject the device:

     sudo eject /dev/sdb
     

gparted - the only way to go with formatting drives and HDs etc. It's available for download in the Ubuntu Software Center, just search for gparted.

Run the below commands to format the usb to fat32 filesystem from terminal,

sudo su
fdisk -l 

(this helps to discover your pendrive /dev/sdxx)

umount /dev/sdxx

then format your device to FAT32

mkdosfs -F 32 -I /dev/sdxx

Where "xx" is from the command fdisk -l which denotes your usb drive's last letters.

sfdisk CLI non-interactive method

echo 'start=2048, type=83' | sudo sfdisk /dev/sdX
sudo mkfs.ext4 /dev/sdX1

erases all data, and creates a single partition that takes up all USB with an ext4 filesystem.

Choose X based on the output of:

sudo lsblk
sudo fdisk -l

For more detailed description of sfdisk see:

fdisk automation

It is also possible to do the same as above with:

printf 'o\nn\np\n1\n\n\nw\n' | sudo fdisk /dev/sdX

but this method is less maintainable than sfdisk, which was designed for Scripting fdisk, specially if you want to create more complex partition tables.

Here are some instruction :

• Plug your flash drive into an empty USB port and back up any data on the drive. Open the main menu, move your cursor over "Accessories" and then click on "Terminal." At the terminal prompt, type sudo apt-get install gparted and press Enter.
• Enter your Ubuntu administrator password when prompted and press Enter. This will download and install GParted, which is an open-source drive partitioning program
• Go to the Ubuntu main menu after the installation is complete, move your cursor over "System," select "Administration" and click "Partition Editor." Enter your administrator password when prompted and click "OK."
• Click on "GParted" in the toolbar. Hover over "Devices" and select your USB flash drive from the list (dev/sdb1, for example). Right-click on the device in the main GParted window and click "Unmount." It may take a few minutes for the device to be unmounted
• Right-click on the device again after it is unmounted and hover over "Format to." Select the desired file system type -- RiserFS, linux-swap, Ext 2, Ext 3, FAT16 or Fat32, for example -- and click "Apply" in the toolbar. Depending on the size of the flash drive, it will take three to four minutes for GParted to complete the process.
• Close GParted after the flash drive is formatted. To mount your USB flash drive, unplug it and then plug it back in. The drive is now ready to store data in the file format you selected.

Restore a USB drive to a standard storage device

Install and use mkusb (mkusb-dus), which can format alias restore a USB drive to a standard storage device (with an MSDOS partition table and a partition with the FAT32 file system). These instructions are also relevant for other drives (memory cards, hard disk drives, HDD, solid state drives, SSD).

If you run standard Ubuntu, you may need an extra instruction to get the repository Universe. (Kubuntu, Lubuntu ... Xubuntu have the repository Universe activated automatically.)

sudo add-apt-repository universe  # only for standard Ubuntu

sudo add-apt-repository ppa:mkusb/ppa  # and press Enter
sudo apt-get update
sudo apt-get install mkusb mkusb-nox usb-pack-efi

See these links with more detailed instructions,

• mkUSB-quick-start-manual.pdf or if the link does not work, this alternate link

mkusb version 12 alias mkusb-dus:

mkusb wipes the first megabyte as a first step of restoring it

Sometimes some data are 'tricking' the software to think that the pendrive does not work, even when it is good, and it is enough to wipe the first megabyte to get rid of those data. You may 'look at' the drive with a tool, that does not recognize or understand correctly the structure of the boot system, for example if it was cloned from an iso file.