This example shows how to use labels using the label attribute on an input component.
<lightning:input type="number" name="myNumber" label="Pick a Number:" value="54" />
The label is placed on the left of the input field and can be hidden by setting variant="label-hidden", which applies the slds-assistive-text class to the label to support accessibility.
Use the $Label global value provider to access labels stored in an external source. For example:
<lightning:input type="number" name="myNumber" label="{!$Label.Number.PickOne}" />
{!format($Label.np.labelName, v.name)}