How to create another partition for storing data?

I think you are confusing mount point with partitions. Partitions mounted under the root, `/` partition will not be affected even if the root partition is corrupted.

FYI: You've provided no OS & release details; but Ubuntu allows you to re-install the system and thus correct package corruption & other system errors; without touching your user files, configs on desktop systems without need for a separate partition.. It's one of the things I **love** about Ubuntu & *flavors*

On a PC, typically Linux uses the *exact same* partitioning scheme as Windows / DOS: either the "old" BIOS MBR partition table scheme, or the "new" UEFI GPT scheme. Linux *can* use other partitioning schemes (e.g. the Apple one), but these are typically not used on PCs. Linux even supported the Windows proprietary LDM scheme, but that isn't even used by Windows anymore, AFAIK. *None* of these have a "root partition", though, so it is very unclear what you are asking. Can you clarify, which *precise* partitioning scheme you are asking about (MBR or GPT), and what you mean by "root partition"?

Of course you can. What you see as '_one partition under the root partition_' is actually a distinctive mechanism of linux file system which _mounts_ that partition to '_some path under the root_'. A partition can always be there '_not under the root_', provided it never ‘_plugs into the matrix_'.

Looking at your question, I think your objective is to have your data preserved if you have to reinstall the OS due to a corruption. The other way to achieve that is to put your entire *home directory* in a separate partition - have a look at this: https://www.howtogeek.com/116742/how-to-create-a-separate-home-partition-after-installing-ubuntu/ That has the advantage of keeping all your data where you expect it, and achieves the objective. I haven’t posted this as an answer as it isn’t what you’re asking to do, but I think it works well.

I had lost my OS several times but then I have a lot of data to lose now, I've gone through the links and one thing that I did right, as per my view, during OS installation, I created a 'partition' or the 'mount point' as I stand corrected by @user68186, at the root as **/my-files - which I gave it 500GB** - this I intend to keep my personal files such as movies and such, in the root now I have, **home - 200GB**, **opt**, **root**, **etc**, I just hope I did it right.

Backup your data. Install gparted and take a screenshot of the app gparted using the screenshot app. Upload the screenshot in imgur.com. Add a link to the uploaded screenshot in your question. This will tell us what you did.

Here it is [screenshot](https://imgur.com/m5scr0S)

It looks like you have created a 700 GB encrypted partition. Did you mount this partition in `/my-files`? Please [edit your question](https://askubuntu.com/posts/1373870/edit) and add all the information you have put in comments. You should also explain **in your question** why your question is not a duplicate. Add the link to the so called duplicate question in your question when you explain why this question is not a duplicate of that.

I sit in a Tesla and translated this thread with Ai: