お母さん、今日の夕飯は何？
Mom, what's for dinner tonight?
彼のお母さんはとても親切です。
His mother is very kind.
Used by a husband to refer to his own wife, especially when speaking to children or in a family context. Carries a warm, familiar tone.
うちのお母さんは料理が上手なんだ。
My wife is a good cook.
Familiar pronoun used to address or refer to an elderly woman older than the speaker, often by children or in a close-knit community. Not used for one's own mother in this sense.
お母さん、これ、落としましたよ。
Ma'am, you dropped this.
隣のお母さんがいつもお菓子をくれる。
The old lady next door always gives me sweets.
She looks a lot like her mother.
Honey, the kids are already asleep.
I help my mother cook every day.
お母さん is the standard polite term for 'mother' usable in most contexts, while ママ is a more intimate, childlike term.