Gravity Forms Pre Submission Hook for

gf_pre_submission_edit_acc.php

<?php

// make sure to change 5he prefix to the one you are using with your forms
add_action( "gform_pre_submission_4", "wp_doin_edit_pre_submission" );

/**
 * @hook gform_pre_submission_4
 */
function wp_doin_edit_pre_submission( $form ) {


	// get the user created arguments and store them in an array
	// note: you may need to alter these, as in case of your numbers, the input_{number} numbers may vary
	$args = array(
		'email' => sanitize_email( $_POST['input_2'] ),
		'fname' => sanitize_text_field( $_POST['input_3'] ),
		'old_pass' => sanitize_text_field( $_POST['input_4'] ),
		'password' => sanitize_text_field( $_POST['input_29'] ),
	);

	// use fictional function to add order 
	wp_doin_update_user( $args );
}

/**
 * Utility to update the user given a number of arguments
 */
function wp_doin_update_user( $args ) {

	if ( defined( 'DOING_CRON' ) || isset( $_GET['doing_wp_cron'] ) )
		return;
	
	// let's make sure this form doesn't run when we are viewing the page while being logged out
	if( !is_user_logged_in() ) 
		return;
		
	// update user email
	if( !empty( $args['email'] ) ){
		$user_id = wp_update_user( array( 'ID' => get_current_user_id(), 'user_email' => $args['email'] ) );
	}

	// update user pass
	if( !empty( $args['password'] ) ){
		$user_id = wp_update_user( array( 'ID' => get_current_user_id(), 'user_pass' => $args['password'] ) );
	}
	
	// update user first name
	if( !empty( $args['first_name'] ) ){
		$user_id = wp_update_user( array( 'ID' => get_current_user_id(), 'user_pass' => $args['first_name'] ) );
	}
}