<div class="flex">
  <form class="grid-container">
    <input class="a" placeholder="Имя">
    <input class="b" placeholder="Компания">
    <input class="c" placeholder="Телефон">
    <input class="d" placeholder="Email">
    <textarea class="e">Сообщение</textarea>
    <button type="submit">Отправить</button>
  </form>
</div>

html,
body {
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
}

.grid-container {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr 1fr 1fr;
  grid-template-rows: 1fr 1fr;
  gap: 20px;
  position: relative;
  grid-template-areas:
    "a a b b e e"
    "c c d d e e";
}
.a {
  grid-area: a;
}
.b {
  grid-area: b;
}
.c {
  grid-area: c;
}
.d {
  grid-area: d;
}
.e {
  grid-area: e;
  resize: none;
}

.a,
.b,
.c,
.d,
.e {
  background: #333;
  color: #fff;
  padding: 6px 4px;
  box-sizing: border-box;
}

::placeholder {
  color: #fff;
}

.grid-container button {
  position: absolute;
  bottom: -50px;
  right: 0;
  background: orange;
  border: none;
  outline: none;
  padding: 10px 14px;
  color: #fff;
  cursor: pointer;
}