Via OCI Console, to edit a block volume (Boot volume), you will need to navigate:

 Block Storage –> Boot Volumes –> Boot Volume Details (edit)

Once you finish this part, a popup will show the commands to be performed on the Linux machine console

sudo dd iflag=direct if=/dev/oracleoci/oraclevda of=/dev/null count=1
echo "1" | sudo tee /sys/class/block/`readlink /dev/oracleoci/oraclevda | cut -d'/' -f 2`/device/rescan

As we are using ubuntu, we are not able to use Oracle tools oci-growfs. But it’s easy, just two command:
# growpart /dev/sda 1;
# resize2fs /dev/sda1

Done. now run df -h you should be able to see the new size.