Linke in theme. Search infinite load more products module that work for prestashop higher than 1.7.7.x
https://addons.prestashop.com/en/navigation-tools/17439-infinite-scroll-premium.html updated version 1.1.13
https://addons.prestashop.com/en/navigation-tools/17439-infinite-scroll-premium.html updated version 1.1.13