inline-block

<style type="text/css">
.box {
    width: 200px;
    height: 100px;
    margin-right: 10px;
}

.elem {
    border: solid #6AC5AC 3px;
    position: relative;
}
</style>
<h2>Вариант 1 (float: left;)</h2>
<div style="position: relative;">
    <div class="box elem" style="float: left;">
        <p>1</p>
    </div>
    <div class="box elem" style="float: left;">
        <p>2</p>
    </div>
    <div class="box elem" style="float: left;">
        <p>3</p>
    </div>
    <div style="clear: left;"></div>
</div>
<h2>Вариант 2 (display: inline-block;)</h2>
<div style="position: relative;">
    <div class="box elem" style="display: inline-block;">
        <p>1</p>
    </div>
    <div class="box elem" style="display: inline-block;">
        <p>2</p>
    </div>
    <div class="box elem" style="display: inline-block;">
        <p>3</p>
    </div>
</div>
<h2>Вариант 3 (position: absolute; left: width+width; top: 0;)</h2>
<div style="position: relative; height: 100px">
    <div class="box elem" style="position: absolute; left: 0px; top: 0px;">
        <p>1</p>
    </div>
    <div class="box elem" style="position: absolute; left: 210px; top: 0px;">
        <p>2</p>
    </div>
    <div class="box elem" style="position: absolute; left: 420px; top: 0px;">
        <p>3</p>
    </div>
</div>
<h2>Вариант 4 (flex)</h2>
<div style="display: flex;">
    <div class="box elem">
        <p>1</p>
    </div>
    <div class="box elem">
        <p>2</p>
    </div>
    <div class="box elem">
        <p>3</p>
    </div>
</div>