Hello, I am Yoshi from NILS Japanese language school.
[N (peason)に　あげます, etc.]
Verbs like あげます, かします, おしえます, etc., need person to whom you give, lend teach, etc. The persons are marked with the particle に.
(Example)
田中さんは　山田さんに　花（はな）を　あげました。
Mr. Tanaka give flowers to Ms. Yamada.
トムさんに　日本語を　教（おし）えます。
I teach Tom Japanese.
*花：　flower
*教えます：　teach

With verbs like おくります, でんわを　かけます, etc., place nouns can be used instead of N (person). In this cae, the particle へ is sometimes used instead of に.
(Example)
会社に[へ]　電話を　かけます。
I’ll call my office.
*電話（でんわ）を　かけます：　call, make a phone call

July 6th News, from NILS Japanese language school.