Upgrade to new SSD

I believe your laptop can accommodate a single 2.5-inch SATA SSD (or HDD). Instructions to remove/install the SSD hardware are in the service manual on the support website.

Assuming the contents aren't encrypted, you can use Macrium Reflect (free version) to clone your SSD to a new, larger 2.5-inch SSD. There's a video here with instructions, along with a link to more detailed instructions. There are at least a couple of different ways to go about it:

• You can temporarily install the new SSD in a USB external enclosure (like this one) and use Macrium to clone all partitions of your existing SSD directly to the new one, enlarging your C: partition in the process. You can then swap the new SSD into your laptop and the old one into the enclosure, reformatting it and using it for whatever you wish.
• Alternately, you could use Macrium to create an image (a compressed backup file) of all partitions of the existing SSD on an external USB backup drive, and create Macrium boot media on a small USB storage stick. You can then install the new SSD in the laptop, boot the laptop from the USB stick and restore the image file from the backup drive onto the SSD.

If you'd prefer a fresh start, you can create Windows 10 installation media using Microsoft's media creation tool, install the new SSD, and install Windows onto it. Your Windows 10 license key is already written in your BIOS firmware. You would, however, have to reinstall apps and restore your files from backups. Drivers would be installed by Windows Update and/or Dell SupportAssist.