How do you transition off formula?

My little one is almost one. We’ve been slowly decreasing the amount of bottles we feed her, and we always offer her food first. The problem is, sometimes she just wants her bottle, mostly at nighttime or in the middle of the night.

1. Is it okay if she’s not 100% off formula / bottles when she’s one?

2. How did you transition your babies to milk? What do you feed them in the middle of the night? Do you give them a sippy cup of warm milk? Or do you give them food?

For reference, my little one is about 50/50 with sleep. Sometimes she sleeps through the night, and sometimes she wakes up in the middle of the night to eat once. When she does that, I feed her in the dark while she’s half asleep. I’m not sure turning the lights on and giving her baby food would be conducive to getting her back to sleep.

Any help would be appreciated.