Cacher is the code snippet organizer for pro developers

/****************************************************************************************************/
/* ADD Custom Partner Field for MyAccount page and change user role to Partner					    */
/****************************************************************************************************/

function wooc_extra_register_fields() {
	?>

	<p class="form-row form-row-wide">
	<label for="reg_partner"><?php _e( 'Partner', 'woocommerce' ); ?> </label>
	<input type="text" class="input-text" name="partner" id="reg_partner" value="<?php if ( ! empty( $_POST['partner'] ) ) esc_attr_e( $_POST['partner	'] ); ?>" />
	</p>

	<?php
}

add_action( 'woocommerce_register_form', 'wooc_extra_register_fields' );

// Change the user ROLE based on our custom field
function my_new_customer_data($new_customer_data){
	
	if (  $_POST['partner'] == 'natur512' ){
		$new_customer_data['role'] = 'partner';
		return $new_customer_data;
	}
	else{
		$new_customer_data['role'] = 'customer';
		return $new_customer_data;
	}
	
}

add_filter( 'woocommerce_new_customer_data', 'my_new_customer_data');