The best answer: Unfortunately, you cannot use the old Surface Pro Type Covers with Surface Pro X. However, you can use them with Surface Pro 7.
Why? Do you use old Type Type covers with Surface Pro X?
The reason you can't use old Type Pro covers with Surface Pro X is because Microsoft has designed the device to be significantly thinner than all other Surface Pro devices before that. This means that older Surface Pro type covers will not fit the Surface Pro X chassis. You will need to obtain the special Surface Pro X type cover from Microsoft, designed to work with the new thickness.
Why get a Surface? Pro X?
While incompatibility with the older Surface Pro Type Covers is unfortunate, it's not a good reason to get away from the Surface Pro X. It has a 2880×1920 13-inch screen, Microsoft's new and powerful SQ1 processor, and It can also be equipped with up to 16 GB of RAM and 512 GB of storage. It has LTE connectivity, two convenient USB-C 3.2 Gen 2 ports and also Windows Hello support. Finally, as noted above, the device is the most compact Surface Pro in history, weighing only 1.68 pounds and a slim design. With how well the device balances power with size and comfort, it's easy to see why Surface Pro X is an exciting product.
The future of Surface Pro
Surface Pro X
The most compact Surface Pro so far
Among its impressive USB-C ports, quality display, SQ1 processor and its large amount of RAM and storage, the Microsoft Surface Pro X seems to be an excellent device .  Get typing
Surface Pro X Type Cover
Tailored for the new arrival
This particular type cover is designed to work specifically with Surface Pro X, which allows you to turn your laptop into a tablet.
If your heart is ready to use one of Microsoft's old Surface Pro Type Covers, then you'll want to check out the Surface Pro 7. The 12.3-inch 2736×1824 screen will probably look great, and it will have incredible computing power thanks to your 10th generation Intel CPUs. In addition, it can be configured with up to 16 GB of RAM and 1 TB of storage space, which should be more than enough for anyone. It also has a camera compatible with Windows Hello, and will be compatible with Wi-Fi 6, the new Wi-Fi standard that provides significantly higher efficiency and speed. There is also a USB-C port, too. It is not as thin or light as the Surface Pro X, but this is what allows it to be compatible with older Surface Pro type covers.