Can I have a two factor code when I first turn my phone on? As it is now it only asks for my 6 digit number

Apple doesn’t request and doesn’t implement a second iPhone passcode.

There’s one passcode or password.

The closest analogs to what you are seemingly requesting are:

• the Apple ID password prompts that exist or can be enabled for certain operations on iPhone (such as Apple app and media purchases),
• enabling biometrics and enabling Stolen Device Protection, and
• enabling and using biometrics and a longer passcode or password.

I’m using an alphanumeric password out past twelve characters, as an example of “longer”.

Two-factor verification is for access to your Apple ID, not for access to your iPhone. See: Two-factor authentication for Apple ID - Apple Support

There is no two-factor option for the iPhone Lock Screen. You can however set a more complicated Lock Screen passcode. See the following from Set a passcode on iPhone - Apple Support

To view options for creating a password, tap Passcode Options. The most secure options are Custom Alphanumeric Code and Custom Numeric Code.