Questions & Answers about Она пригласила друзей.
Because it is past tense feminine singular.
In Russian past tense, the verb agrees with the subject in gender and number:
- он пригласил = he invited
- она пригласила = she invited
- оно пригласило = it invited
- они пригласили = they invited
So with она, you need пригласила.
The dictionary form is пригласить.
That is the infinitive, meaning to invite.
So:
- пригласить = to invite
- пригласила = invited (feminine subject)
This verb is perfective, which means it presents the action as a completed whole.