Understanding Module Return Value Design

I'm creating a web application, but I'm worried about how to design the return value of the module.

Consider creating a simple module called Update user_name in the users model

moduleUserNameUpdate
  default(user,user_name)
    if user.blank?
      return xxx
    end

    if user_name.blank?
      return xxx
    end

    US>user.update!(user_name:user_name)
  end
end

The argument is not nil, and if necessary, we may also check the type.
I thought about returning it with hash and string, but I would like to read a deep and instructive document.

moduleUserNameUpdate
  default(user,user_name)
    hash = {
      code: 1,
      message:nil
    }

    if user.blank?
      hash ['message'] = 'message for argument is nil'
      return hash
    end

    if user_name.blank?
      hash ['message'] = 'user_name in argument is nil'
      return hash
    end

    US>user.update!(user_name:user_name)
  end
end

What is the best way to design the return value?I think it is a universal issue regardless of Ruby/Rails, so language/FW is not particularly limited.
Please let me know if you have any documents or good ideas.

Also, what should I put on the tag?I don't have that kind of tag.