Custom Meta Box for Edit Page Screen

I’ve set up a custom meta box (according to a tutorial) so that it appears on the Edit Post screen. This is working well.

I’d like to know how to modify the code below so that the custom meta box would appear in the Edit Page screen instead. I tried changing the 4th parameter of the add_meta_box() function from ‘post’ to ‘page’, but I still can’t get the custom meta box to appear in the Edit Page screen.

Your help would be greatly appreciated.

<?php

/*
Plugin Name: Custom Meta Box Template
Plugin URI: http://example.com/
Description: Provides a starting point for creating custom meta boxes.
Author: Author
Version: 1.0
Author URI: http://example.com/
*/

/**
 * Adds a meta box to the post editing screen
 */
function prfx_custom_meta() {
    add_meta_box( 'prfx_meta', __( 'Meta Box Title', 'prfx-textdomain' ), 'prfx_meta_callback', 'post' );
}
add_action( 'add_meta_boxes', 'prfx_custom_meta' );

/**
 * Outputs the content of the meta box
 */
function prfx_meta_callback( $post ) {
    wp_nonce_field( basename( __FILE__ ), 'prfx_nonce' );
    $prfx_stored_meta = get_post_meta( $post->ID );
    ?>

        <label for="meta-text" class="prfx-row-title"><?php _e( 'Example Text Input', 'prfx-textdomain' )?></label>
        <input type="text" name="meta-text" id="meta-text" value="<?php if ( isset ( $prfx_stored_meta['meta-text'] ) ) echo $prfx_stored_meta['meta-text'][0]; ?>" />

    <?php
}

/**
 * Saves the custom meta input
 */
function prfx_meta_save( $post_id ) {

    // Checks save status
    $is_autosave = wp_is_post_autosave( $post_id );
    $is_revision = wp_is_post_revision( $post_id );
    $is_valid_nonce = ( isset( $_POST[ 'prfx_nonce' ] ) && wp_verify_nonce( $_POST[ 'prfx_nonce' ], basename( __FILE__ ) ) ) ? 'true' : 'false';

    // Exits script depending on save status
    if ( $is_autosave || $is_revision || !$is_valid_nonce ) {
        return;
    }

    // Checks for input and sanitizes/saves if needed
    if( isset( $_POST[ 'meta-text' ] ) ) {
        update_post_meta( $post_id, 'meta-text', sanitize_text_field( $_POST[ 'meta-text' ] ) );
    }

}
add_action( 'save_post', 'prfx_meta_save' );

/**
 * Adds the meta box stylesheet when appropriate
 */
function prfx_admin_styles(){
    global $typenow;
    if( $typenow == 'post' ) {
        wp_enqueue_style( 'prfx_meta_box_styles', plugin_dir_url( __FILE__ ) . 'meta-box-styles.css' );
    }
}
add_action( 'admin_print_styles', 'prfx_admin_styles' );