In Russian you don't need a linking verb in sentences like "This is..." or "She is..." when you use them in the present tense. So the right variant is "Это - мама" or "Она - мама"

1) "Она есть мама" - is not correct, you have to say "Она - мама" (without есть). And you'll get - "She's a mother". 2) "Это мама, это папа" - is correct. You can translate it as "She's a mother, he's a father" or "This is a mother, this is a father".