Hello ayush and welcome to Seven Forums.
That H: drive could be a factory installed recovery partition. It probably has all the necessary files to restore your computer to factory specifications and make it just like it was on the day you bought it.
The fact that other files have been stored on that partition could be a problem, especially if they changed the recovery files.
There's a free utility called MiniTool Partition Wizard. One of the features is to see what files are in a partition. If you install the software you'd select the "Explore Partition" option and follow the prompts. This might let you determine if the non-recovery files can be deleted or moved to another partition. How to Explore Partition - help of partition manager - Partition Wizard.