I have a 1 TB hard disk. But while installing KDE I aloted 50 GB for the OS partition during installation. Can I access the rest of the storage? If yes, how?

Rest of hard disk is partitioned?
if yes, it might be accessible from dolphin. Same as if it is partitioned as a Windows' partition I. e.

If no, you must create a partition and format it, using KDE Partition Manager or Gparted. If that partition will be accessible.from Wind3, format it as NTFS. If it will be accessible from Linux only, you can format it as ext4.

After it, it would be accessible using Dolphin.

otherwise, if your question is if you can add unused free space to the Linux OS (/) partition, the answer is yes, you can. Using KDE Partition Manager or Gparted too.

Keep in mind, please, that working with partitions (creating, deleting or modifying) can result in data's loss so it's recommended backuping your data.

First time on forum. Hi.
Many happy hours on Kubuntu. Up grading to 20.10. Formatted 1TB /dev/sda. Used GPARTED to set up partitions. KDE Partition Manager running from Kubuntu Installer on usb thumb drive won't allow a partition larger than 130GB. GPARTED had my /home partition at 256GB. KDE PartManage shows about 128GB. It Will NOT allow anything over 130GB. Drive is UEFI-GPT 1 TB. Is there really a partition size limit?

That is strange, this should just work, unless you have an adjacent partition that prevents extending an existing one. I partitioned both SSDs with the KDE Partition manager on my system, no size restrictions I can see, so the fault is not he partition manager.

GPT on the other hand might be the source of the problem, but that is pretty much out of our hands, as this needs to be configured properly in the BIOS.

Thank you so much for getting back to me. You see, I set-up my clean sda with GPARTED. Well, that was a waste of effort because Kubuntu only lets you install through Partition Manager. That is, if you make size changes because Partition Manager has read the GPARTED table wrong. By deleting partitions that Partition Manager got wrong and making new partition, you get to proceed to INSTALL.