Hi @MichelaAlvisi ,
As per my understanding it is not currently possible to email a list of companies, you can only email contacts from HubSpot not companies When you send an email to the company, it emails the contacts of the companies. There is not a way to email a company currently. You can submit this as a feature to the HubSpot Ideas form. You can access the page here: HubSpot Ideas
Regards.