If I understand you correctly, you are asking about an Input Dialogue and that isn’t available in the current version of Ninox. This can be modified to suit your needs...

https://ninoxdb.de/en/forum/technical-help-5ab8fe445fe2b42b7dd39ee7/an-alternative-to-the-input-dialog-5bc40cd413e90e0528f18b5d

S Moore  Hi, I know it's been five years, but if you or anyone else is still interested in a Text Input Popup, this is your formula:

html("<style>
.floating-button {
    padding: 10px 20px;
    font-size: 14px;
    color: white;
    background-color: #007bff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}
[popover] {
    width: max-content;
    padding: 10px;
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: opacity 0.2s ease;
}
</style>
<button class='floating-button' popovertarget='popover' popovertargetaction='toggle'>Click me</button>
<div id='popover' popover>
    <h2>Text</h2>
    <textarea rows='6' cols='50' placeholder='I am a popover with a text area where you can type in your info. You can also use the draggable corner to resize the text area, which is handy for longer entries. Give me a try by writing something...'></textarea>
    <button class='floating-button' style='float: right; margin-top: 10px;' popovertarget='popover' popovertargetaction='hide' onclick='saveText();'>Add</button>
</div>
<script>
function saveText() {
    // add logic here
};
</script>")

Just let me know if you need a hand with the "Add" button logic. You'll find more info in the Dashboard_v11_1.