When you accept an invite for a Final Draft 13 site license, you'll be asked to create a password. This password is stored securely by Final Draft's licensing provider.
You will use this password along with your email to sign into Final Draft 13 after downloading it and installing it onto your computer.
If you forget your password, your administrator cannot reset it, nor can anyone from Final Draft. You would need to follow the steps in this article to reset your password: How do I reset my Final Draft 13 password?