// Declare inside your Unreal Class
DECLARE_DELEGATE_OneParam(FMyActionDelegate, float);

//Do in function like BeginPlay or the StartupModule function of your Plugin
UInputSettings* Settings = UInputSettings::GetInputSettings();
Settings->AddActionMapping(FInputActionKeyMapping(TEXT("MyTestAction"),EKeys::T));
Settings->SaveKeyMappings();

InputComponent->BindAction<FMyActionDelegate>(TEXT("MyTestAction"),EInputEvent::IE_Pressed,this,&MyClass::MyFunctionHandler,-0.1337f);