Viewing Memory and Storage Information
View storage and memory information, change the default storage location, and format the microSD card.
Not all devices support microSD cards.
1. Open 
Settings.
2. Touch Memory & storage to view storage information for your internal storage and microSD card.
3. From there, you can:
– Format the microSD card: Touch SD card > Format > Erase & format to clear all data from the microSD card. Back up your files before formatting the card to avoid losing your data.
– Set the default storage location: Touch Default location and set the default storage location to the internal storage or microSD card.
Questions about your Huawei Mate 10? Post in the comments!
Huawei Mate 10 Manual [PDF]