On the Visitor Visa application it says I have to prove my relationship to the host that is inviting me, in this case it is my best friend who is inviting me to her wedding. And on the instructions it says that all I need to do is upload a copy of the inside back cover of the inviter's passport showing the inviter's parents, if applicable and the other instructions is only applicable to marriage partners and parents. But is it a good idea to upload any other evidence? And if so which type of evidence would be best?