Put content inside a form. You can also change the button type input to a submit type, this way the form is sent automatically on click.
<form method="POST" action="yourURL.php">
<input type="text" id="myText" name="myElement" value="Mickey">
<a href="test.php?id=javascript:document.getElementById('myText').value;">
<input type="submit" value="Click"></a>
</form>
More information on forms: MDN
Whether you use GET or POST as a method, you'll be able to access the content of the form through PHP variables: $_GET, $_POST or the generic $_REQUEST.
More information in the PHP documentation
Note: PHP uses the name attribute of your HTML elements for those variables. Make sure to add this attribute to your HTML elements otherwise you'll have a hard time getting a value from $_REQUEST['myText']. I added the attribute holding the value "myElement" in the above code. It is accessible through PHP by typing $_REQUEST['myElement'].
Content sent through GET method is visible in the URL,
like this: www.example.com/test.php?var1=test&var2=test
$_POSTover$_GET- for me$_POSTis cleaner and doesn't make the url look weird.