If you are looking to "develop a text" (perhaps for a notification alert or an automated voice), you can use the built-in or Spoken Content features on modern iOS devices to turn text into speech or extract text from old screenshots.

Once you've downloaded a sound file (usually in .m4r or .mp3 format), you can set it as your notification or ringtone:

: Use a computer or a cloud service to get the file onto your device.