I grew up spelling it Mama but increasingly I’m seeing momma and I get autocorrected to Mamma.
How do you write it?
Mum.
It’s always been ‘mom’ in our family.
We were raised to call our parents Mama and Papa. By the time we were tweens (although the word didn’t exist then 
) we thought Papa sounded silly so we called him Pop which persists to today. “Mama” eventually morphed into Mom or Ma (never Mommy).
I used momma. I grew up in the south. GA to be specific.
I spell it (in my head anyway) “mama”. The only time I see it spelled “mamma” is in crossword puzzles when the answer is the play / song “Mamma Mia”. Can’t think offhand if I’ve seen it spelled “momma”.
If I was going to spell the word, then Mama is how I would spell it.
OTOH, I don’t call my mother mama, I call her Mom or Mommy.
Mama is how I would spell it if it rhymes with “drama”. Momma is how I’d spell it if it rhymes with “comma”. I have heard both pronunciations here in the Northeast. They seem to be two different (but obviously related) terms rather than two different pronunciations of the same term.
The way I pronounce “drama” and “comma”, they rhyme with each other. /dɹɑmə/ and /kɑmə/. How do you pronounce them?
“Mom” or “Mommy”.
Mom.
When my mom died three years ago, I realized I had become the eldest. My mom and dad were both only children and I am their oldest child. So I told my brother, sister, their kids and mine that everyone had to call me pappy. And I’ve stuck with it.
Why no option for Mmomaa
He’s from Maine! It’s anyone’s guess. 
They rhyme for me too but I am not from heah.
Mummy. Canadian, with British roots.
It was always Mom in our household and those of my friends. Mama and Papa just sounded very trailer park trashy. I do not mean to offend anyone. That was just how it was for me growing up. I have a high school acquaintance on FB that is my age (56) and she refers to her mom as my Mama. It sounds even worse coming from an adult (in my head).
Yes.
“Drama” and “mama” rhyme with “llama.” The first syllable of “comma” and “momma” rhymes with “mom” and “bomb.”
Mama. My kids alternate between Mum and Mama.
For me (from California), all those words rhyme with each other. Mama, drama, llama, and comma.
I only call my mom, Mom, but I refer to myself as my cats’ momma. Definitely spelling it like I pronounce it, as “mom” with an “a” at the end, which is different from “mama.”