Sort posts archive by name.

WordPress - sort archive by name.php

function sort_archive_by_name( $query ) {
  /*
   * Change the 'if' condition to the taxonomy/category you want to apply the new sorting
   */
  if ( is_tax('product-category') ) {
    $query->set( 'orderby', 'title' );
    $query->set( 'order', 'ASC' );
  }
}
add_action( 'pre_get_posts', 'sort_archive_by_name' );