For selected default option you need to add “default” to checkbox field.

I make an example:
if you want checkbox-1 selected default to “Option 1” you need to add default:1

[checkbox checkbox-1 default:1 “Option 1” “Option 2”]

Let me know

Ok, I got it one part using the contact form default values from shortcode attributes

https://contactform7.com/getting-default-values-from-shortcode-attributes/

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For example, let’s say you have a field named “checkbox-1” for the checkbox-1:

[checkbox* checkbox-1]
To get the default value from shortcode attributes, add the default:shortcode_attr option to the form-tag:

[checkbox* checkbox-1 default:shortcode_attr]
Then, add an attribute with the same name as the field (“checkbox-1” in this case) into the shortcode for the contact form:

[contact-form-7 id=”123″ title=”Contact Form” checkbox-1= “Option 1”]

Add the following code snippet to your theme’s functions.php file:

add_filter( 'shortcode_atts_wpcf7', 'custom_shortcode_atts_wpcf7_filter', 10, 3 );

function custom_shortcode_atts_wpcf7_filter( $out, $pairs, $atts ) { 
$my_attr = 'destination-email';

if ( isset( $atts[$my_attr] ) ) {
$out[$my_attr] = $atts[$my_attr];
}
return $out;
}

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This step is working.

Can I have a second attribute?
I don’t know how to code in PHP and add the option to have a second attribute.

I’ve created a contact form 7 form, with the plugin for the conditional fields.

I’d like to know if it is possible to have a shortcode of the form with already some options selected.

Like below:

<label> Name (*)
    [text* your-name] </label>

<label> Email (*)
    [email* your-email] </label>

<label> Phone
    [tel* tel-1] </label>

[checkbox checkbox-1 exclusive "Option 1" "Option 2"]

[group group-1][checkbox* checkbox-2 exclusive "Option A" "Option  B" "Option C" "Option D"][/group]

[submit "Submit"]

The objective will be to have a shortcode to the form with for example the Option 2 and Option D already selected.