How to create typewriter effect?

Few ways to go about this. The least complicated is creating a variable first, something like "myURL". Then create shape (such as a square) just off of your stage. Create a trigger on this shape so that when the timeline starts, your myURL variable is set to the full URL.

Make copies of this shape and delete an additional letter from each copy until you end up with one shape with a single letter. Now arrange your shapes on the timeline, pretty close together, to produce an animation that builds the letters one at a time.

Now when you add %myURL% to a text field, you can position it wherever you want without having to worry about a one letter at a time build arrangement.