Questions & Answers about Мы здесь надолго.
In Russian, the verb to be is usually omitted in the present tense.
So:
- Мы здесь = We are here
- Мы здесь надолго = We are here for a long time / We’re here to stay
If you wanted past or future, Russian would use forms of быть:
- Мы были здесь недолго = We were here only briefly
- Мы будем здесь долго = We will be here a long time
So the missing are is completely normal.
Надолго means for a long time, for long, or sometimes idiomatically to stay.
In this sentence, it gives the idea that the stay is not short-term:
- Мы здесь надолго = We’ll be here for quite a while
- depending on context, even We’re here to stay
It is an adverb, so it describes the duration of the situation.