The property management company asked the security guard to go to the store outside to buy security clothes. Is this property management company formal?

Whether a property company is formal or not is not what we say. As long as people have a nationally recognized business license and qualification certificate, it is formal. As for letting security guards go outside to buy work clothes, this behavior should violate the requirements of the labor law, which clearly stipulates that enterprises must provide work clothes free of charge. You can check the relevant regulations.