In this After Effects tutorial, Emily Meng covers how to add typewriter effects to text.
You're going to go down here to where it is and you're going to, under animate, click character offset. You're going to add a property of opacity right here. You're going to leave that at zero, and you don't need a keyframe for that.
You're to go to range selector and then you're going to start a keyframe here at zero and you're going to move your indicator over to wherever you want it. I'm going to set this to five seconds. We're going to make it 100 here. Under advanced, you do your smoothness. We're going to go back just to make sure we have it all selected. Your smoothness is going to be zero.
If I did this right, it should work. Yep, so that's how you do that. You can do it with any time that you want. It's pretty simple to do.
Here's the final result: