<?php

if (isset($_POST["checkboxInput"])) {
    if (in_array("value1",$_POST["checkboxInput"])) {
        echo "This is value 1<br/>";
    }
    if (in_array("value2",$_POST["checkboxInput"])) {
        echo "This is value 2<br/>";
    }
    if (in_array("value3",$_POST["checkboxInput"])) {
        echo "This is value 3<br/>";
    }
    if (in_array("value4",$_POST["checkboxInput"])) {
        echo "This is value 4<br/>";
    }
}
?>

<form method="post">
    <input type="checkbox" name="checkboxInput[]" value="value1">Value 1<br/>
    <input type="checkbox" name="checkboxInput[]" value="value1">Value 1<br/>
    <input type="checkbox" name="checkboxInput[]" value="value1">Value 1<br/>
    <input type="checkbox" name="checkboxInput[]" value="value1">Value 1<br/>
    <input type="submit" value="submit"/>
</form>

<?php

    if (isset($_POST["radioGroup1"]) || isset($_POST["radioGroup2"])) {
        echo "Group 1 value: ".$_POST["radioGroup1"]."<br/>";
        echo "Group 2 value: ".$_POST["radioGroup2"];
    }
    ?>

    <form method="post">
        <div>
            <input type="radio" name="radioGroup1" value="radio1">Радио 1</input>
            <input type="radio" name="radioGroup1" value="radio2">Радио 2</input>
        </div>

        <div>
            <input type="radio" name="radioGroup2" value="radio3">Радио 3</input>
            <input type="radio" name="radioGroup2" value="radio4">Радио 4</input>
        </div>
        <input type="submit" value="submit"/>
    </form>