Customize file upload functionality for input elements.

custom.html

.upload-btn-wrapper input[type=file] {
    position: absolute; 
    font-size: 14px;
    top: 0;
    color: #141414;
    right: 0;
}
input[type="file"]::-webkit-file-upload-button {
	 background: transparent;
	 border: 0;
	 padding: 1em 2em;
	 cursor: pointer;
	 color: #fff;
	 border-radius: 0.2em;
	 opacity: 0;
}
 input[type="file"]::-ms-browse {
	 background: transparent;
	 border: 0;
	 padding: 1em 2em;
	 cursor: pointer;
	 color: #fff;
	 border-radius: 0.2em;
} 

$('input[type="file"]').change(function () {
			if ($(this).val() != "") {
				$(this).css("color", "#616161");
			} else {
				$(this).css("color", "#141414");
			}
		}); 

  <label for="">Resume</label>
                        <button class="btn">Attach Resume</button>
                        <input type="file" required name="resume" />