How do I send WordPress form leads to a specific contact list?

Hello @OliviaB971 ,

If you're using our integrated forms with your WordPress site, then you can give contacts the ability to select what lists they want to be a part of while signing up.

Otherwise, you should be able to manually export your contacts from your WP account, and upload that CSV file into your Constant Contact account. You may need to check with WordPress support on how the export process works, or there may be other apps / addons you need to utilize for that functionality. 

See also:

Formatting contact files for import

Install the Constant Contact plugin for WordPress