The Decode area of the Setup view allows you to choose which code types you want to enable, and to configure the parameters for those code types.
In the example below, all code types are enabled.
You can add code types by clicking in an empty section of the field where code types are displayed, and then selecting the desired code types from the dropdown menu.
You can also enable one of several postal code options using the Postal Option dropdown menu shown below.
Clicking the gear icon at the bottom of the Decode section brings up Symbology Settings. This allows you to configure every parameter for every available code type.
Data Matrix error correction parameters are shown in this example, but you can configure any parameter for any of the code types in the list shown below. All parameter changes for all code types take effect immediately.