fictizia-settings-api-1.php

<?php
add_action( 'admin_menu', 'fictizia_add_settings_menu' );
function fictizia_add_settings_menu() {
	add_submenu_page( 'fictizia-main', 'Settings', 'Settings', 'manage_options', 'fictizia-settings', 'fictizia_display_settings_menu' );
}

function fictizia_settings_init() { 
	register_setting( 'OPTIONS_GROUP', 'OPTIONS_GROUP', 'SANITIZE_CALLBACK' );

	add_settings_section( 'SECTION_ID', __( 'SECTION_TITLE', 'fictizia' ), 'SECTION_CALLBACK', 'MENU_SLUG' );
	add_settings_field( 'FIELD_ID', __( 'FIELD_TITLE', 'fictizia' ), 'FIELD_CALLBACK', 'MENU_SLUG', 'SECTION_ID' );
}
add_action( 'admin_init', 'fictizia_settings_init' );


function SECTION_CALLBACK() { 
	echo __( 'This section description', 'fictizia' );
}

function fictizia_display_text_field(  ) { 
	?>
		<input type='text' name='OPTIONS_GROUP[NAME_OF_THE_FIELD]' value="">
	<?php
}


function fictizia_display_settings_menu() {
	?>
		<div class="wrap">
			<h2><?php echo esc_html( get_admin_page_title() ); ?></h2>

			<form action="options.php" method="post">
				<?php settings_fields( 'OPTIONS_GROUP' ); ?>
				<?php do_settings_sections( 'MENU_SLUG' ); ?>

				<?php submit_button( null, 'primary', 'OPTIONS_GROUP[submit_settings]' ); ?>
			</form>
		</div>
	<?php
}