The graft will be where the stem takes a jog above the roots - look there.

Some may be propagated by cuttings, but it's clear that this one was grafted (or budded which is a type of graft). The swollen portion below the trunk and above the rootstock indicates the place where this was done.

Otherwise trees don't have elbows unless they have been cut back or died back, grown a new top above that point.