Questions & Answers about Её голос ровный и спокойный.
Here её means her in the possessive sense: her voice.
In this sentence, её is being used like a possessive word before a noun, just like my, your, her in English.
A useful thing to know: Russian его, её, and их often work as possessive words meaning:
- его = his
- её = her
- их = their
So:
- её голос = her voice
- его голос = his voice
- их голос = their voice
Unlike many other Russian pronouns, these possessive forms do not change to match the gender or number of the noun after them.
In Russian, the verb to be is usually not expressed in the present tense.
So where English says:
- Her voice is calm
Russian simply says:
- Её голос спокойный
That means ровный и спокойный works as the predicate without any present-tense is.
If you were talking about the past or future, Russian would use forms of быть:
- Её голос был спокойным. = Her voice was calm.
- Её голос будет спокойным. = Her voice will be calm.