Hello,
Please make a child theme to keep your changes safe add the following code on your child themes function.php file

function education_hub_get_slider_details( $input ) {

		$featured_slider_type   = education_hub_get_option( 'featured_slider_type' );
		$featured_slider_number = education_hub_get_option( 'featured_slider_number' );

		switch ( $featured_slider_type ) {

			case 'featured-page':

				$ids = array();

				for ( $i = 1; $i <= $featured_slider_number ; $i++ ) {
					$id = education_hub_get_option( 'featured_slider_page_' . $i );
					if ( ! empty( $id ) ) {
						$ids[] = absint( $id );
					}
				}
				// Bail if no valid pages are selected.
				if ( empty( $ids ) ) {
					return $input;
				}

				$qargs = array(
					'posts_per_page' => esc_attr( $featured_slider_number ),
					'no_found_rows'  => true,
					'orderby'        => 'post__in',
					'post_type'      => 'page',
					'post__in'       => $ids,
					'meta_query'     => array(
						array( 'key' => '_thumbnail_id' ), // Show only posts with featured images.
					),
				);

				// Fetch posts.
				$all_posts = get_posts( $qargs );
				$slides = array();

				if ( ! empty( $all_posts ) ) {

					$cnt = 0;
					foreach ( $all_posts as $key => $post ) {

						if ( has_post_thumbnail( $post->ID ) ) {
							$image_array = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'education-hub-slider' );
							$slides[ $cnt ]['images']  = $image_array;
							$slides[ $cnt ]['title']   = esc_html( $post->post_title );
							$slides[ $cnt ]['url']     = esc_url( get_permalink( $post->ID ) );
							$slides[ $cnt ]['excerpt'] = education_hub_the_excerpt( apply_filters( 'education_hub_filter_slider_caption_length', 50 ), $post );

							$cnt++;
						}
					}
				}
				if ( ! empty( $slides ) ) {
					$input = $slides;
				}

			break;

			default:
			break;
		}
		return $input;

	}

then change the number besides ‘education_hub_filter_slider_caption_length’ which is now 50 to your required number of words you want to show.

Hope this helps