This is the standard way to simulate text being written in real-time.
: Change the Paint Style in the effect settings to "Reveal Original Image" so the brush acts as a mask revealing the text underneath. Method 2: Masking (Smoother Results) premiere pro cc 2014
By applying an effect to a "parent" master clip, the change would automatically propagate to every instance of that clip used across the timeline. This is the standard way to simulate text