Hi,
Currently, there’s no option to achieve this because the font size of text implements according to the screen width. If you persist in it, you can add custom CSS code inside
WP-Admin Dashboard > Tower Panel > General Options > Custom CSS Code

@media (max-width: 480px){
 .codeless_slider .swiper-slide .content h5{
    font-size: 24px !important /* Change Heading font size */;
    line-height: 32px !important;
 }
 .codeless_slider .swiper-slide .content h1 {
    font-size: 16px !important /* Change description font size */;
    line-height: 26px !important;
 }
}

Thanks,