Простой и легкий пример для вас:
label {
margin:20px 0;
position:relative;
display:inline-block;
}
span {
padding:10px;
pointer-events: none;
position:absolute;
left:0;
top:0;
transition: 0.2s;
transition-timing-function: ease;
transition-timing-function: cubic-bezier(0.25, 0.1, 0.25, 1);
opacity:0.5;
}
input {
padding:10px;
}
input:focus + span, input:not(:placeholder-shown) + span {
opacity:1;
transform: scale(0.75) translateY(-100%) translateX(-30px);
}
/* For IE Browsers*/
input:focus + span, input:not(:-ms-input-placeholder) + span {
opacity:1;
transform: scale(0.75) translateY(-100%) translateX(-30px);
}
<label>
<input placeholder=" ">
<span>Placeholder Text</span>
</label>