Most keyloggers track what buttons you tap on the virtual or hardware keyboard. Others track where on your screen you are tapping. Others make screen recordings. There are a few things you can do to protect your users from the listed above keyloggers:

1. Ensure your app doesn't allow screenshots/screen recordings.
2. Make a custom keyboard - a grid with buttons.
3. When a button is clicked, trigger a few random system inputs to create a misleading appearance, making it look as if the input is "encrypted." Only include the actual button pressed in the visible output, and make sure to remove the random inputs without prompting the keyboard's delete function.