If you print an individual message while using the conversation view in Gmail, you may accidentally print the entire thread. Here's how to print a single email from Gmail without printing the entire conversation using the web version of Gmail on any browser.
To print a single email from a longer thread or conversation, follow these steps.
Open the conversation with the message you want to print. Select the message.
Select the three dots to the right of the message you want to print, then choose Print from the drop-down menu.