Example

$form = new Form('plugins-signature-pad-form-1', 'vertical');

$form->addInput('hidden', 'user-signature', '', 'Sign to confirm your agreement', 'data-signature-pad=true, data-background-color=#336699, data-pen-color=#fff, data-width=100%, data-height=300, data-clear-button=true, data-clear-button-class=btn btn-sm btn-warning, data-clear-button-text=clear, data-fv-not-empty, data-fv-not-empty___message=You must sign to accept the license agreement');

<div class="bs5-form-stacked-element mb-3">
    <label for="user-signature" class="form-label">Sign to confirm your agreement</label>
    <input id="user-signature" name="user-signature" type="hidden" value="" data-signature-pad="true" data-background-color="#336699" data-pen-color="#fff" data-width="100%" data-height="300" data-clear-button="true" data-clear-button-class="btn btn-sm btn-warning" data-clear-button-text="clear" data-fv-not-empty data-fv-not-empty___message="You must sign to accept the license agreement">
    <canvas id="user-signature-canvas" class="signature-pad-canvas"></canvas>
</div>