XPS 8930, upgrade Drive C

This is how I would do it all in Windows no third party tool

https://www.dell.com/community/en/conversations/optiplex-desktops/how-to-clone-ssd-to-another-ssd-without-third-party-tool/652b338043dbba53b173f0b7?keyword=Clone

If you also have an internal D: HDD in your XPS 8930, is Windows storing its default folders with all your personal files on that drive instead of on C: (M.2 NVME) SSD?  If not, moving those folders to the D: drive might free up enough space on the SSD so you don't need to upgrade it, as least not now. Read about moving default folders in Win 10 or Win 11.

And if you have an internal HDD, you could also uninstall some of your apps in Windows on C: drive and reinstall them but direct the installations onto the D: drive to free up even more space. Note: if you use Microsoft Office, it will object to being moved onto D: so just leave it on C: SSD.

If you don't have an internal HDD now, it might be easier and less expensive to install an HDD and then move Windows default folders and personal files, and even some apps onto the new HDD. 

If you're going to install a new M.2 NVME Samsung SSD to replace the old one, you probably should change the BIOS SATA Operation setting from RAID to AHCI on XPS 8930 first because Samsung's software and SSDs don't work well with BIOS set to RAID. 

This can be easily done, but you will need to reconfigure BIOS and Windows to use AHCI while the old SSD is still installed, before you create an image for the new SSD. And it has to be done the right way:

1. Open CMD prompt window, run as administrator
2. Copy-paste this command, which will start Windows in Safe Mode the next time you boot: bcdedit /set {current} safeboot minimal and press Enter
3. Restart the computer and tap F2 when you see the Dell screen to enter BIOS setup
4. Change SATA Operation from RAID to AHCI. Don't change anything else.
5. Save the change and exit Setup. Windows will automatically boot in Safe Mode.
6. Open CMD again, as in step #1
7. Copy-paste this command, which will start Windows in Normal Mode the next time you boot: bcdedit /deletevalue {current} safeboot and press Enter
8. Reboot and Windows will automatically start with AHCI drivers enabled.
9. Now you're ready to image the SSD and then swap in the new one.

You can use Macrium Reflect (free for 30 days) to create an image of the entire C: SSD and save it on an external USB HDD. Then use Macrium to create a bootable USB you'll need to boot the PC.

When that's done, swap in the new SSD. Plug in the Macrium USB and boot PC via the F12 menu option to boot from USB, and Macrium will load automatically.

Since the new SSD will be larger than the existing one, use Macrium to copy all partitions from the saved image onto that new drive one at a time, saving C: partition for last. Only the size of the last partition copied can be expanded. So if C: isn't moved last, all the extra space on new SSD will be wasted.

@redxps630​ It looks very simple. I have to consider this option. Thank you.

@RoHe​ Thank You. I'm not sure if I'm ready for this procedure. My knowledge about deep PC configuration is very limited. I will think about it.

Why not using Dell procedure
Guide to Disk Cloning with SupportAssist OS Recovery | Dell Canada

I also have a system XPS 8930 Tower, purchased back in 2019.
The first thing I did was to install an internal 4TB Seagate Hard Drive as D.
Operating System (Win 11) and applications are on C-drive.
All data-files are located on D-drive.

A couple of years ago, I installed an extra Seagate 4TB Hard Drive as H.
That drive is being used as a backup for D-drive.
Whenever I'm finish working for the day, I run Vice-Versa, backing up from D to H drive.
This works great for me.

Just my two cents worth.

@Marmadoc  - You could follow that Dell procedure, except you'll need to buy an external NVME housing to connect the new SSD while you clone the existing SSD onto it because the XPS 8930 motherboard only has one M.2 NVME connector = extra cost for something you'd use maybe 1 time. 

Even if you do it that way, you should change BIOS to AHCI first, especially if you get a  Samsung SSD.  (Check other SSD manufacturer's recommendations about RAID vs AHCI too.) 

You didn't tell us if you also have an internal D: HDD. Using that HDD or installing one, could be an easier and less expensive way to free up space on your existing 256 GB SSD simply by moving personal files and some apps off the SSD and onto the HDD. 

Like @Tedco, I also store all my personal files on the D: HDD in my XPS 8930, and have Firefox browser and some other apps installed on that drive too, leaving lots of space free on my C: SSD.

Maybe you have a geeky relative or friend who can help you...?

@RoHe​ Thank you for suggestion. I moved all my documents to D drive. It helped but not solved the problem. I reinstall some apps to D drive as well. So far no problem - but when I open 

C:\Users\MyName - here is over 50GB of data, and this blocks my C drive.

50 GB is only ~20% of the 256 GB on your SSD.  What do you mean "block" your C: drive?

The real question is how much total free space is available on the SSD now that you've moved your docs and some apps onto D: drive ?

Have you tried running a Windows Disk Cleanup and then an Optimize your SSD?

@RoHe​ less than 20GB