Board Thread:Episode Discussions/@comment-25319479-20180524132716/@comment-33658396-20180528035058

It was very heavily implied that Boruto learned his moves through seeing someone using it without anyone teaching him. The gaiden arc ,Mist arc and Graduation arc are the arcs that implied these.

The mist arc when we first saw him practicing wind style on Iruka he contemplated on how Mitsuki used it.

During the graduation arc Kakashi asked if Naruto taught him the shadow clone technique which he denies

Of course all of these moves can indeed hint as if Konohamaru taught these to him, but when Boruto went to him for help on the rasengan "he was surprised that lord sevenths son wants training from him" as said from him to Sasuke. I probably did not copy the exact words for some of these but I can insure you it means the same thing.

All of this implies that prior to the Rasengan he was indeed self taught. But note that I am talking about anime Boruto and not movie or manga boruto since it seems as though all three of them have a slightly different canon.