Change the color of the SVG element.
If the SVG element is capable of it, you can change its fill color with fill-[theme color] and stroke color with stroke-[theme color]. If you don't modify any of these colors, the default fill color is always currentColor.
<svg width="30" height="30" class="fill-secondary" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><title>keyboard-arrow-return</title><path d="M16.147,1.952H12.238a1.5,1.5,0,0,0,0,3h3.909a4.852,4.852,0,1,1,0,9.7H7.137a.25.25,0,0,1-.25-.25V11.27a1,1,0,0,0-1.707-.707L.293,15.449a1,1,0,0,0,0,1.414L5.18,21.75a1,1,0,0,0,1.707-.707V17.906a.25.25,0,0,1,.25-.25h9.01a7.852,7.852,0,1,0,0-15.7Z"/></svg>
<svg width="30" height="30" class="fill-success" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><title>diagram-arrow-down</title><path d="M5.5,15.215A1,1,0,0,0,4.767,16.9l6.16,6.633a1.458,1.458,0,0,0,2.146,0l6.16-6.633a1,1,0,0,0-.733-1.681H15.25a.25.25,0,0,1-.25-.25V1.5A1.5,1.5,0,0,0,13.5,0h-3A1.5,1.5,0,0,0,9,1.5V14.965a.25.25,0,0,1-.25.25Z"/></svg>
<svg width="30" height="30" class="fill-white stroke-secondary" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><title>design-tool-pen-station</title><path d="M21.459,16.5a4,4,0,0,0-4-4h-.5V12a1,1,0,0,0-1-1h-12a1,1,0,0,0-1,1v9.5a2.5,2.5,0,0,0,2.5,2.5h9a2.5,2.5,0,0,0,2.5-2.5v-1h.5A4,4,0,0,0,21.459,16.5Zm-4,2h-.25a.249.249,0,0,1-.25-.25v-3.5a.249.249,0,0,1,.25-.25h.25a2,2,0,1,1,0,4Z"/><path d="M5.649,2.864a.249.249,0,0,0,.017-.429L3.3.905a.5.5,0,0,0-.75.511l.422,2.53a.25.25,0,0,0,.366.178Z"/><path d="M3.646,5.094a.25.25,0,0,0-.1.334l2.22,4.3a.5.5,0,0,0,.445.27h3a.5.5,0,0,0,.438-.741l-3.026-5.5a.252.252,0,0,0-.339-.1Z"/><path d="M13.539,7.293l-.007,0a3.525,3.525,0,0,1-.636-.348.252.252,0,0,0-.361.084L11.293,9.257A.5.5,0,0,0,11.73,10h1.832a.5.5,0,0,0,.468-.323L14.7,7.893a.251.251,0,0,0-.2-.337,3.526,3.526,0,0,1-.68-.156C13.727,7.368,13.633,7.333,13.539,7.293Z"/><path d="M17.017,2.815a3.679,3.679,0,0,0-2.81-2.8.5.5,0,0,0-.536.761c.529.805.21,1.282-.353,1.994a3.621,3.621,0,0,0-.542.819,2.037,2.037,0,0,0,1.151,2.783,2.044,2.044,0,0,0,2.245-.257A3.363,3.363,0,0,0,17.017,2.815Z"/></svg>