Если уже есть align-items: center; Но ниже нужно переписать его на align-items: flex-end;

.intro__inner {
    height: 852px;
    background-color: #F4F6F5;
    border-radius: 59px; 
    margin-top: 53px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 80px 0 120px;
}

.intro__title {
    font-weight: 900;
    font-size: 96px;
    line-height: 120px;
    margin-bottom: 40px;
}

.intro__subtitle {
    font-weight: 400;
    margin-bottom: 32px;
}

.intro__block {
    display: flex;
    gap: 34px;
}

.intro__block-button {
    border: none;
    padding: 19px 40px;
    background: #000;
    color: #fff;
    font-size: 32px;
    font-weight: 500;
    border-radius: 10px;
    cursor: pointer;
}

<div class="intro">
            <div class="container">
                <div class="intro__inner">
                    <div class="intro__text">
                        <h1 class="intro__title">
                            LET'S <br>
                            EXPLORE <br>
                            UNIQUE <br>
                            CLOTHES. <br>
                        </h1>
                        <h3 class="intro__subtitle">
                            Live for Influential and Innovative fashion!
                        </h3>
                        <div class="intro__block">
                            <img src="images/Vector button.svg" alt="" class="intro__block-svg">
                            <button href="/" class="intro__block-button">Shop now</button>
                        </div>
                    </div>
                    <div class="intro__imagen">
                        <img src="images/png-intro.png" alt="" class="intro__img">
                    </div>
                </div>
            </div>
        </div>