Hi @IFMarch
I would recommend using the HubSpot Sales Extension for Gmail and simply keep sending emails via GMail.
This allows you to send emails from GMail and log/track them in HubSpot. As much as I like HubSpot, I prefer sending emails via Gmail and that way I can keep working out of my normal inbox.
If people want to send emails via HubSpot they will have to set up their email signatures in HubSpot.
Frank