<div class="radikalwp-float">
  <input type="text" placeholder=" " required>
  <label>نام و نام خانوادگی<//label>
<//div>

.radikalwp-float { position: relative; width: 300px; }
.radikalwp-float input {
  width: 100%;
  padding: 16px 14px 8px;
  font-family: inherit;
  font-size: 14px;
  color: #0f172a;
  border: 1.5px solid #cbd5e1;
  border-radius: 12px;
  outline: none;
  background: #fff;
  transition: border-color .25s;
}
.radikalwp-float label {
  position: absolute;
  top: 50%;
  right: 14px;
  transform: translateY(-50%);
  color: #94a3b8;
  font-size: 14px;
  pointer-events: none;
  transition: all .2s ease;
  background: transparent;
  padding: 0 4px;
}
.radikalwp-float input:focus { border-color: #6366f1; }
.radikalwp-float input:focus + label,
.radikalwp-float input:not(:placeholder-shown) + label {
  top: 0;
  font-size: 11px;
  color: #6366f1;
  background: #fff;
}