CTA Button Example

button.css

.cta-button {
    max-width: 333px;
    width: 100%;
    position: relative;
}
.cta-button .ss-button {
    border-top-left-radius: 30px;
    border-bottom-right-radius: 30px;
    width: 273px;
    height: 63px;
    background-color: blue;
    display: table-cell;
    text-align: center;
    vertical-align: middle;
    text-decoration: none;
    color: white;
    font-weight: 700;
    font-size: 1.25rem;
    line-height: 1.938rem;
    position: relative;
    transition: width 0.5s ease;
}
.cta-button::before {
    content: "";
    position: absolute;
    right: 15px;
    clip-path: polygon(70% 0, 100% 50%, 70% 100%, 0% 100%, 30% 50%, 0% 0%);
    width: 31px;
    height: 27px;
    top: 17.5px;
    background-color: blue;
}
.cta-button::after {
    content: "";
    position: absolute;
    border-bottom-right-radius: 30px;
    background-color: white;
    width: 85px;
    height: 63px;
    right: 0;
    top: 0;
    z-index: -1;
    border: 3px solid blue;
}

index.html

<div class="cta-button">
    <a class="ss-button" href="#">Contact Us</a>
</div>

Live demo:
https://www.awesomescreenshot.com/video/6807645?key=72f85fa40d5a158c4d9fccb0ccf92838