I adjusted a similar answer

css:

.footer-signature {
    display: flex;
    justify-content: space-between;
    flex-direction: row;
    text-align: center;
    margin-top: 2em;
}

.signature-space {
    margin-top: 4em;
}

html:

 <div class="footer-signature">
    <div>
        <div>Pemohon</div>
        <div class="signature-space">
            (..........................................)
        </div>
    </div>

    <div>
        <div>Petugas</div>
        <div class="signature-space">
            (person name)
        </div>
    </div>

    <div>
        <div>Operator</div>
        <div class="signature-space">
            (person name)
        </div>
    </div>
</div>

I changed the flex direction to row and grouped text in divs, thus giving you this look:

space-between sets the three elements far apart, you may change this by different justify-content values, 'center' with proper margin / spacing looks the most similar to what you want.