One way to animate text to appear in After Effects is to create a flicker-on effect.
With your text layer selected, choose the Animate button by your text property and select Opacity. Set a keyframe for 0% where you want your animation to begin, and a keyframe for 100% where you want the animation to end.
Then, twirl down Range Selector 1 and set keyframes for the Start value: 0% at the beginning and 100% at the end. Under Advanced, turn Randomize Order on. Then, set a keyframe for Random Seed at the beginning of your animation. Choose a different value at the end of the animation.
Now, you’ll have a flicker-style effect that makes your text visible. You can alter the random seed value to try out different looks, as well as retime your keyframes for pacing adjustments.
Watch this short After Effects tutorial for a quick demonstration:
