Some email clients such as Gmail and Outlook will show a snippet of preview text next to the Subject line in the inbox. By default, this includes the first few lines of text from your email as teaser text for your recipient.
Use the Preview Text field in the email editor to control the preview text and optimize it to improve your open rate. Please note, that it is not possible to apply formatting to the preview text, such as: font, size or color.
Please note that Outlook may not show any preview text, even when you leave the Preview Text box empty in HubSpot.