The imperative verb forms are used to give orders or advice, to urge strongly, and to exhort. It is a simple tense—in the sense that it isn't compound—and has only one form, the present. Furthermore, you can address your command only to an informal form of "you": tu or voi, depending on whether you are talking to one or more people.
When conjugating a first-conjugation Italian verb, the familiar singular (tu) command is the same as the third-person singular (Lei) form of the present indicative, and the plural voi command is the same as the voi form of the present indicative (see the table below).
FIRST-CONJUGATION VERB IMPERATIVES
INFINITIVE
TU
VOI
cantare
Canta!
Cantate!
mangiare
Mangia!
Mangiate!
parlare
Parla!
Parlate!
The familiar commands for regular -ere and -ire verbs are the same as the tu and voi forms of the present indicative (see the table below).
SECOND- AND THIRD-CONJUGATION
VERB IMPERATIVES
INFINITIVE
TU
VOI
dormire
Dormi!
Dormite!
finire
Finisci!
Finite!
pulire
Pulisci!
Pulite!
salire
Sali!
Salite!
scrivere
Scrivi!
Scrivete!
vendere
Vendi!
Vendete!
Although the imperative conjugation has a form you're already familiar with, there are some Italian verbs that have irregular forms for the familiar commands in the tu and voi forms (see the table below).
SECOND- AND THIRD-CONJUGATION
VERB IMPERATIVES
INFINITIVE
TU
VOI
andare (to walk)
Va'!
Andate!
avere (to have)
Abbi!
Abbiate!
dare (to give)
Da'!
Date!
dire (to say, to tell)
Di'!
Dite!
essere (to be)
Sii!
Siate!
fare (to make)
Fa'!
Fate!
sapere (to know)
Sappi!
Sappiate!
stare (to stay)
Sta'!
State!
From:https://www.dbfei.com/Article/yidaliyu/201311/7672.html