An input doesn’t have innerHTML – it has value. Change:

label.innerHTML = addedField.innerHTML;

to

label.innerHTML = addedField.value;

I’m trying to add to my form a new input field and label.
But when I use getElementByID and innerHtml functions but I get an empty string back in the new label.
Here is the form code:

    <form action="/" method="POST">
    <div id="container"></div>
    <input type="text" name="newItem" id="newF" placeholder="New Item" class="inp" autocomplete="off">
    <button type="button" onclick="addField()">+</button>
    <button type="submit" class="btn btn-success">Send</button>

Here is the JS code:

    function addField(){
      // Container <div> where dynamic content will be placed
        let container = document.getElementById("container");
        let addedField = document.getElementById("newF");
    
        let label = document.createElement("label");
        console.log(addedField.innerHTML);
        label.innerHTML = addedField.innerHTML;
    
        // Create an <input> element, set its type and name attributes
        let input = document.createElement("input");
        input.type = "text";
        input.name = "member";
        input.className = "inp";
    
        container.appendChild(label);
        container.appendChild(document.createElement("br"));
        container.appendChild(input);
    }