Huawei
Pin the Keyboard to One Side auf Huawei
On Huawei phones, the Microsoft SwiftKey Keyboard is set to full width by default, which is why the keys always stretch across the whole screen. There is no toggle labeled one-handed mode; instead, EMUI lets you drag the keyboard border to shrink it and push it toward either edge.
This behavior sits inside the keyboard app itself, not in general system settings, so changes only apply to SwiftKey and not to other input methods you might have installed.
To move the keyboard, open Settings ➔ System & updates ➔ Languages & input ➔ Microsoft SwiftKey Keyboard ➔ Layout & keys ➔ Resize. Drag the left or right border inward to narrow the keyboard, then confirm with OK.
Once resized, the keyboard stays pinned to that side until you repeat the steps and drag the border back to full width. This is useful for one-handed typing on large-screen devices, but it also reduces the number of visible keys, which can slow down typing if you frequently switch between languages or symbols.