Just like @Trude0 says, the type of response and type of action required by Airbnb is different depending on whether you receive these spams as an information request or a trip request.
If in doubt, please read the guide on the subject below and I hope that this will make you more confident on how to handle them:
@Peace-Stays0 For inquiries just reply (a dot will do) and then don't accept/reject as rejection will likely affect your search placement. For requests to book you need to accept or reject.