Change hdd on my cloud

I own this model WDBCTL0020HWT i want to change my hdd to lrager disk like 4TB or 6TB.
I can change? if yes which type of hdd i need? green?blue?red?

The single bay My Cloud units typically have a WD Red drive inside. You can however in reality use just about any SATA hard drive within the My Cloud enclosure. Use the form search feature, magnifying glass icon upper right, to search for “unbrick”. There are numerous guides detailing how to properly setup a blank hard drive on the My Cloud device.

There is also user Fox_exe’s guides that some here have used to unbrick their single bay My Cloud drive.

First gen single bay v3.x/v4.x My Cloud:
https://drive.google.com/file/d/0B_6OlQ_H0PxVbzZac0plbkZKeGM/view

Second gen single bay v2.x My Cloud:
https://drive.google.com/file/d/0B_6OlQ_H0PxVQVhnLVJOdDZISUU/view