Confirmation GDPR

Hello,

I need to send out some newsletters including a form to ask people receiving it to confirm they are ok with GDPR. I'd like this form is automatically fullfilled with informations from the database. Sometimes I used {%CurrentUser.UserName #%} and things like that to fulfill some fields but in this case, I don't know what to use ... : {%Subscriber.UserName #%} or {%CurrentUser.SubsciberName #%} or anything else.

Please give me the good syntax ?

Thanks