に：maker for "place", to, in へ：maker for "derection", for, toward OK：日本へ行きたいです。 OK：日本に行きたいです。 Practically no difference. OK: 日本に着きました。arrived at Japan OK？: 日本へ着きました。 ※ 日本へ着く is logically not a good expression but often said, because 日本に（NIHON・NI ) is a little tongue twister and people tend to avod it. OK：あの人への想い my feeling of love toward him NG：あの人にの想い OK: あの人に届け、わたしの想い OK：あの人へ届け、わたしの想い 　　　※ 届く（とどく）：reach Again, the へ and に as a marker for destination is almost always interexchangeable. OK?： I think not so good, but often said and surely makes sense, nobody misunderstands you and nobody regards it impolite.

1」にandへ to indicate the arrival point or moviment direction， one can be replaced for the other． Ex:彼氏に呼び出されて駅(に)(へ)行きました。 I was called by my boyfriend and went to the station. ２」にand へ can not be replaced one for the other when it is decided to be an idiomatic word such as "お風呂に入る、バスに乗る". But in the first case there is no difference.