<div class="container">
  <div class="box-1">
    <h2>Box 1</h2>
    <p>some text</p>
  </div>
  <div class="box-2">
    <h2>Box 2</h2>
    <p>some text</p>
  </div>
</div>

div {
  border: 2px solid blue;
}

.container {
  display: flex;
  flex-direction: row;
}

.box-1, .box-2 {
  flex: 50%;
}