Creates 2 additional fields (company and title) on Easy Digital Download's register account form, and saves them to the newly registered user's profile

gistfile1.php

<?php

/**
 * Add company field to EDD's registration form
*/
function my_child_theme_register_account_fields() { ?>
	
	<p id="edd-user-company-wrap">
		<label for="edd-company">
		<?php _e( 'Company', 'my-child-theme' ); ?>
		<?php if( edd_no_guest_checkout() ) { ?>
			<span class="edd-required-indicator">*</span>
		<?php } ?>
		</label>
		<span class="edd-description"><?php _e( 'Your company name', 'my-child-theme' ); ?></span>
		<input name="edd_company" id="edd-company" class="edd-input" type="text" placeholder="<?php _e( 'Company', 'my-child-theme' ); ?>" title="<?php _e( 'Company', 'my-child-theme' ); ?>"/>
	</p>

	<p id="edd-user-company-title-wrap">
		<label for="edd-company-title">
		<?php _e( 'Title', 'my-child-theme' ); ?>
		<?php if( edd_no_guest_checkout() ) { ?>
			<span class="edd-required-indicator">*</span>
		<?php } ?>
		</label>
		<span class="edd-description"><?php _e( 'Enter your company title', 'my-child-theme' ); ?></span>
		<input name="edd_company_title" id="edd-company-title" class="edd-input" type="text" placeholder="<?php _e( 'Title', 'my-child-theme' ); ?>" title="<?php _e( 'Title', 'my-child-theme' ); ?>"/>
	</p>

<?php }
add_action( 'edd_register_account_fields_after', 'my_child_theme_register_account_fields' );

/**
 * Make both the company and title field required at checkout
*/
function my_child_theme_validate_account_fields( $valid_data, $data ) {

	if( ! edd_no_guest_checkout() )
		return;

	if( empty( $data['edd_company'] ) )
		edd_set_error( 'invalid_company', __( 'Please enter a company.', 'my-child-theme' ) );

	if( empty( $data['edd_company_title'] ) )
		edd_set_error( 'invalid_company_title', __( 'Please enter a company title.', 'my-child-theme' ) );

}
add_action( 'edd_checkout_error_checks', 'my_child_theme_validate_account_fields', 10, 2 );

/**
 * Add new section to WP profile and create custom fields
*/
function my_child_theme_extra_profile_fields( $user ) { ?>

 <h3><?php _e( 'Additional Information', 'my-child-theme' ); ?></h3>

 <table class="form-table">
	 <tr>
	   <th><label for="company"><?php _e( 'Company', 'my-child-theme' ); ?></label></th>
	   <td>
	     <input type="text" name="company" id="company" value="<?php echo esc_attr( get_the_author_meta( 'company', $user->ID ) ); ?>" class="regular-text" /><br />
	   </td>
	 </tr>
	 <tr>
	   <th><label for="company"><?php _e( 'Title', 'my-child-theme' ); ?></label></th>
	   <td>
	     <input type="text" name="title" id="title" value="<?php echo esc_attr( get_the_author_meta( 'title', $user->ID ) ); ?>" class="regular-text" /><br />
	   </td>
	 </tr>	 
 </table>
<?php }
add_action( 'show_user_profile', 'my_child_theme_extra_profile_fields', 10 );
add_action( 'edit_user_profile', 'my_child_theme_extra_profile_fields', 10 );

/**
 * Update the user's profile with the new field values on user registration
*/
function my_child_theme_user_register( $user_id ) {

	if( ! edd_no_guest_checkout() )
		return;

    if ( isset( $_POST['edd_company'] ) )
        update_user_meta( $user_id, 'company', $_POST['edd_company'] );

     if ( isset( $_POST['edd_company_title'] ) )
        update_user_meta( $user_id, 'title', $_POST['edd_company_title'] );

}
add_action( 'user_register', 'my_child_theme_user_register' );

/**
 * Save the fields when the values are changed on the profile page
*/
function my_child_theme_save_extra_profile_fields( $user_id ) {

	if ( !current_user_can( 'edit_user', $user_id ) )
		return false;

	update_user_meta( $user_id, 'company', $_POST['company'] );
	update_user_meta( $user_id, 'title', $_POST['title'] );

}

add_action( 'personal_options_update', 'my_child_theme_save_extra_profile_fields' );
add_action( 'edit_user_profile_update', 'my_child_theme_save_extra_profile_fields' );