Hello, @Anoop S Kumar,
Please copy and paste the below-given CSS code to XStore >> Theme Settings >> Theme Custom CSS >> Global and check back your site after removing the browser cache.
.et_element.et_b_header-search .input-row.flex.align-items-center select#product_cat-400 {
padding-left: 10px !important;
}
Regards 8Themes Team.