I’ve had a few days off having just had my AZ vaccination jab, but I have finally got round to finishing my Typewriter Effect utility and putting it up in the “resources” section of my website:
If you want to create an effect that is overlaid on top of another video clip then be aware that, because of the way the effect is created, you cannot have a transparent background, so you will have to use a “green screen” technique. e.g. if your text is white (#ffffff), choose a black (#000000) background (or vice versa) and use the “chroma key” filter to turn the background transparent.
This is just one way producing a typewriter effect, there are other techniques using just Shotcut itself, @jonray has produced an excellent instructional video (My new YouTube tutorial - Typewriter Text) on how to do this, including how to include typewriter sound effects.
The app/utility looks like: