I can't found "erase all contents" in my iMac "system preference. Please help

If you can't use Erase All Content and Settings

System Preferences includes Erase All Content and Settings only when using macOS Monterey on a Mac with Apple silicon or a Mac with the Apple T2 Security Chip. If this feature isn't available or doesn't work on your Mac, follow these steps instead:

• To restore factory settings, learn what to do before you sell, give away, or trade in your Mac.
• To erase, follow the steps to erase a Mac with Apple silicon or the steps to erase an Intel-based Mac using Disk Utility.

Monterey Missing Erase All Contents and S… - Apple Community