Indirect object nouns and pronouns (i pronomi indiretti) answer the question to whom? or for whom? In English, the word "to" is sometimes omitted:
We gave a cookbook to Uncle John.
We gave Uncle John a cookbook.
In Italian, the preposition a is always used before an indirect object noun:
Ho regalato un libro di cucina allo zio Giovanni. (I gave a cookbook to Uncle John.)
Perché non regali un profumo alla mamma? (Why don't you give Mother some perfume?)
Puoi spiegare questa ricetta a Paolo? (Can you explain this recipe to Paul?)
Indirect object pronouns replace indirect object nouns. They are identical in form to direct object pronouns, except for the third-person forms gli, le, and loro. For all the forms, see below.
ITALIAN INDIRECT OBJECT PRONOUNS
PERSON
SINGULAR
PLURAL
I
mi (to/for me)
ci (to/for us)
II
ti (to/for you, informal)
vi (to/for you, informal)
III
lo, la (to, for him/her)
li, le (to/for them, masculine/feminine)
La (to/for you, formal)
Li, Le (to/for you, formal, masculine/feminine)
All indirect object pronouns except loro and Loro precede a conjugated verb, just like the direct object pronouns (loro and Loro follow the verb):
Le ho dato tre ricette. (I gave her three recipes.)
Ci offrono un caffè. (They offer us a cup of coffee.)
Parliamo loro domani. (We'll talk to them tomorrow.)
Similarly, indirect object pronouns attach to infinitives, which lose their final -e:
Non ho tempo di parlargli. (I have no time to talk to him.)
If the infinitive is preceded by a conjugated form of dovere, potere, or volere, the indirect object pronoun may also precede the conjugated verb:
Voglio parlargli./Gli voglio parlare. (I want to talk to him.)
Also note that le and gli are never elided before a verb beginning with a vowel or an h:
Le offro un caffè. (I offer her a cup of coffee.)
Gli hanno detto "Ciao!". (They said "Ciao!" to him.)
The table below provides a few common Italian verbs that are often used with indirect object nouns or pronouns.
VERBS THAT TAKE ON INDIRECT OBJECTS
dare
to give
dire
to say
domandare
to ask
(im)prestare
to lend
insegnare
to teach
mandare
to send
mostrare
to show
offrire
to offer
portare
to bring
preparare
to prepare
regalare
to give (as a gift)
rendere
to return, give back
riportare
to bring back
scrivere
to write
telefonare
to telephone
From:https://www.dbfei.com/Article/yidaliyu/201311/7669.html