Hello and welcome to Apple Support Communities, garivera!
We understand you want to enable the one-handed typing on your iPhone 12 mini. We'd be happy to provide information to help you accomplish this.
Try the steps here to enable it: About the keyboards settings on your iPhone, iPad, and iPod touch
"Turn on one-handed typing
Use one-handed typing on your iPhone to make it easier to type with one hand. Here's how:
- Touch and hold or .
- Tap to move the keyboard to the left. Tap to move the keyboard to the right.
- When you're done, touch and hold or . Then tap to bring your keyboard back to its usual setting.
You can also turn on one-handed typing from Settings > General > Keyboards and tap One Handed Keyboard. You need an iPhone 6 or later to use the one-handed keyboard. This feature excludes iPhone SE (1st generation) and iPod touch."
Have a great day!