Also if you want to create dynamic emails like on each email sending you want to vary the content for the email, then you can use Transactional Emails of HubSpot. It allows to insert dynamic content everytime when we send an email to a contact.
If you want to create emails directly on HubSpot based on your code, design or text, I would recommend you to have a look at https://designers.hubspot.com/
It allows to create email templates in HubSpot as per our design