As this tab has inbuilt storage of 16GB but we get only about 13.47GB which is insufficient if you install HD games like GTA, NFS, MCB5, NOVA3, etc . But you can root this Mi Pad with the Official Developer ROM at en.miui.com/download-229 and after it download an app called link2sd from Play Store and Move App & Games to Memory Card.
I highly recommend SanDisk 32Gb Class 10 Ultra Memory Card.
I hope that this information is helpful to you and Root process you can watch on YouTube by Searching root redmi tab it is the similar process. By Dheeraj