Hello, Dear Daria!

1. To remove search button on top header navigation menu please click WP Dashboard => Appearance => Customize => Additional CSS, then paste this code here :

.home .search_modal a.search_modal_button {
    display: none;
}

2.  To remove  the last pink line left under services please click WP Dashboard => Appearance => Customize => Additional CSS, then paste this code here :

section.bottom_pink_line_big .container:before {
       display: none;
}

3. To remove round picture prom testimonials please click WP Dashboard => Appearance => Customize => Additional CSS, then paste this code here :

.testimonials-single-carousel.testimonials.owl-theme blockquote .avatar img {
    display: none;
}

4. To edit Margins/ paddings from footer paste this code:

.page_footer .container {
    padding-bottom: 50px;
}

Save changes, clear your cache and check result!

Best Regards!