You can use code to Custom CSS box to create hexagon button in Squarespace.
header#header a.btn {
clip-path: polygon(20% 0%, 80% 0%, 100% 50%, 80% 100%, 20% 100%, 0% 50%);
padding: 30px 36px !important;
display: inline-block;
position: relative;
transition: transform 0.3s ease;
border: none !important;
}
Result
You can adjust these values.
