I will know someone's gender, age and other information if I send an email invite for the survey.

I noticed that I can upload a file of participants upload but can I add particular values to the URL to populate answers so the user will not have to answer those in the survey?

For example, I'll send John Doe an email to take the survey and I know that John is a 30 year old male so I don't want to waste his time by asking in the survey. I'd like the send the answers to the hidden questions in the email.

Or maybe I can join tables if I know his token and survey id?

Thanks,
Kevin

Since you already know these attributes before sending an invitation to your participants you don't need to use URL parameters.

You can use attributes, which you can access via Expression manager
www.limesurvey.org/manual/Survey_participants#Manage_attributes

It works great! I uploaded a csv file with the attributes and then added conditional questions on the attributes. Thanks.