Hi @KStajniak,
Regardless of whether your email is created using the drag and drop editor or a HTML template, you should see this formatting menu bar when you click into a text module:
If you want to add a personalization token right in the HTML code, you would follow this syntax:
{{ object.internalpropertylabel }}
For example, the syntax for the personalization token for the first name would be {{ contact.firstname }}. The space character inside of the curly brackets is important.
Generally, you can look up the internal property label in the property settings, clicking the </> symbol to the right of the property name:
Best regards!