I would do two kinds of backup depending on what is wrong with the laptop. First I would image the disk using a program like Acronis True Image across the USB port to an external disk. I would just buy a cheap hard drive for this, not a SSD. It should be at least slightly larger capacity as your existing internal SSD. I would also make a separate backup of your data. You can just do that to the cloud with google drive or one of the other cloud providers.
The reason I would do both is this. If the repair is simple and doesn't impact the mother board much, you will probably just be up an running fine without using either backup. If somehow the SSD is damaged or corrupted during the repair and the repair is minor and does not impact the mother board much, once a new SSD is installed, you will be able to copy the image backup to the new SSD using a program like True Image. This means you don't have to reinstall windows and all your applications. When windows in installed, it looks at the hardware and tailors your copy of windows to the hardware. Sometimes when hardware is repaired and components are changed out, windows doesn't want to run properly and you have to reinstall it. If that turns out to be the case, you will want to have a copy of your user data files available in an format where they can be individually accessed (unlike an image clone of the disk).
Hope it works out,
Jack