Either have your friend register with the bot, so the other account is made and already assigned with the teamspeak identity.
Code:
!register <name>
!password <password>
EX:
!register kanalumaddela
!password mypassword
or
Create a separate user account for your friend and assign it to their teamspeak identity. (Settings -> User Accounts -> Add User Account)
If they want to be able to access to web panel you need to open port 8087 and give them your public ip (or just use one of those free hostname services, so they directly can't see it). If you don't know how to port forward, google is your friend.