go to crowler and duel him if u win he will sign a new pda and give it to you. go to
fontaine and she will ask for you to let crowler watch you shag her. then she will duel
with you

I am confused because I have tried the favourite answer to this question out many a time
and I haven't got the signature of him

talk to crowler the slacker and ask for a duel if you win he'll give you the signature if
you lose let's say you win

how i can get a partner and i want zane to be my partner

you must find atticus after finishing the game in the beach at 6 am and you must talk to
him he will say 'whats up' then you must reply 'the sky' then he will battle with you but
to obtain the signature that fonda likes you must win 10 times and then he will give you
his signature.