I have a puppy here bred by myself and would like the stud dog owner to be in partnership with me, now can i add her affix onto the kennel club name?
emma x

Presumably, you would (or have) registered the puppy with your affix as a prefix. To add the stud owner's affix, I think you would have to transfer the puppy to her ownership, she could then add her affix as a suffix & you could then transfer the puppy into joint names (nice little earner for the KC!) If the stud dog owner happened to have bred both the dam & the sire then you could have both names as affixes. There may be another way, but I'm not aware of it!

That is exactly how I had to do it for the dog I had in ownership but you can send off all the paperwork at once so they just send the one certificate.
Becky