iPhone : Settings > General > Keyboards > Auto-Correction
Android: Settings > Languages and Input > Android Keyboard > Text Correction
@singlemaltgirl if you have a search bar on your phone (not a browser search bar), you can type Auto Replace or Suggest Text Corrections and see what happens.
@Valkyrie_D i appreciate this. but i think i once googled this, too. i have an android. there's no languages & input so i couldn't follow the instructions. i knew there was a reason i haven't been able to do it before. 🙄