Bootstrap class: .collapsed

    <div class="accordion" id="accordionExample">
        <div class="accordion-item">
        <h2 class="accordion-header" id="headingOne">
            <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#accordionCollapseOne" aria-expanded="false" aria-controls="accordionCollapseOne">
            Lorem ipsum dolor sit amet consectetur.
            </button>
        </h2>
        <div id="accordionCollapseOne" class="accordion-collapse collapse" aria-labelledby="headingOne" data-bs-parent="#accordionExample">
            <div class="accordion-body">Lorem ipsum dolor sit amet consectetur adipisicing elit. Illo quam dolore ea pariatur veniam rem voluptatibus harum magni reiciendis maiores!</div>
        </div>
        <div class="accordion-item">
            <h2 class="accordion-header" id="headingTwo">
                <button class="accordion-button collapsed" type="button" data-bs-toggle="collapse" data-bs-target="#accordionCollapseTwo" aria-expanded="false" aria-controls="accordionCollapseTwo">
                Lorem ipsum dolor, sit amet consectetur adipisicing.
                </button>
            </h2>
            <div id="accordionCollapseTwo" class="accordion-collapse collapse" aria-labelledby="headingTwo" data-bs-parent="#accordionExample">
                <div class="accordion-body">Lorem ipsum dolor sit amet consectetur adipisicing elit. Enim ea nam exercitationem alias ad, repellendus eligendi ipsa rerum voluptatum aperiam.</div>
            </div>
        </div>
    </div>Copy code