settings.php

<?php
/**
 * Settings
 */

add_shortcode('procore-form', 'show_procore_form');
function show_procore_form(){
    global $wp;
	$auth_url = 'https://app.procore.com/oauth/authorize';
	$access_token = '51836e36-9655-4abf-8da5-2ded95b05fb6';
	$client_id = 'bc1d2d378d6c0bc0aa2b5d0f172e0152c0868e2439e04adf12e46691ce04d65f';
	$client_secret = '36b6774f4b0b919edd0068494946e386c47343836007a92512af0a0f6c6caf13';
	$current_url = home_url(add_query_arg(array(),$wp->request));
	$headless_url = 'urn:ietf:wg:oauth:2.0:oob';
    return '<a href="'.$auth_url.'?response_type=code&client_id='.$client_id.'&redirect_uri='. $headless_url .'">Connect to Procore</a>';

}

/**
 * Tell WP we use a setting - and where.
 */
add_action( 'admin_init', 'procore_register_setting' );
function procore_register_setting()
{
    add_settings_section(
        'procore_api_id',
        'Procore Settings',
        'procore_description',
        'general'
    );

    // Register a callback
    register_setting(
        'general',
        'procore-token',
        'trim'
    );
    // Register the field for the "avatars" section.
    add_settings_field(
        'ads',
        'Procore Access Token',
        'procore_access_settings',
        'general',
        'procore_api_id',
        array ( 'label_for' => 'procore_api_id' )
    );
}

/**
 * Print the text before our field.
 */
function procore_description()
{
    echo '<p class="description">Insert procore access token here.  To obtain one '.do_shortcode('[procore-form]').'</p>';
}

/**
 * Show our field.
 *
 * @param array $args
 */
function procore_access_settings( $args )
{
    $data = esc_attr( get_option( 'procore-token', '' ) );

    printf(
        '<input type="text" name="procore-token" value="%1$s" id="%2$s" />',
        $data,
        $args['label_for']
    );
}