Questions & Answers about Poslužićemo hranu i piće.
Because the verb form -ćemo already shows that the subject is we. Serbian often leaves out subject pronouns when the verb ending makes the subject clear.
You could add mi if you want emphasis or contrast:
Mi ćemo poslužiti hranu i piće.
It is the future tense: specifically future I in Serbian grammar.
The basic verb is poslužiti = to serve, and ćemo is the future auxiliary meaning we will. So poslužićemo means we will serve.
In Serbian, with many verbs whose infinitive ends in -ti, the future auxiliary can attach directly to the verb.
So:
poslužiti + ćemo → poslužićemo
A separate version is also possible in a sentence such as:
Mi ćemo poslužiti hranu i piće.
When ćemo is written separately, it usually appears in the second position of the sentence.
The dictionary form is poslužiti.
That is the infinitive form, the one you would find in a dictionary. In this sentence it appears in a future-tense form: .