My Microsoft Lumia 950XL has text auto correct turned off, when my grandson was playing with it.
Which I don't know what it is or how to use, how do I turn it back, went to settings, keyboard, but couldn't get any further as stated for other lumia phones.
Go to Settings, Time & Language, Keyboard. Touch the keyboard you want to change, I assume English (US). Check / uncheck all the options as you would like.