Deleting a Partition
Deleting a partition is simple. Select the partition you want to delete and click the delete icon on the top menu and then click apply icon. Deleting a partition will erase all the data in that partition, so be careful while using it.
Disk Partitioning in Ubuntu using GParted
Disk Partitioning is a process of separating disks into one (or) more logical areas so that user and system work on them independently. When a partition is created, the disk will store the information about the location and size of partitions in the partition table. With the partition table, each partition can appear on the operating system as a logical disk, and users can read and write data on those disks. Learn more about Disk Partitioning in Linux