A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
In testing, when I add an Appear animation to a placeholder full of text, the Effect Options dropdown is set to By Paragraph and each paragraph animation is set to On Click. So by default, text should be appearing as you describe. Somehow your slide has had different settings applied.
If you're still having a problem, please let us know which animation you've chosen, and what version number appears in File>Account>About PowerPoint. You can also upload your deck to a cloud service and post a share link here, so we can have a closer look.