What are the best ways to introduce a 1 year old to taking food ?
The best way is to start early and slowly.
My 5 months old daughter eats vegetable soup with powder milk everyday. She likes mineral water as well. From 3 months old we started to put a few spoons of vegetable soup in her milk to get her used to and see if there is some taste she likes better and now she can eat anything (liquid).
For your 1 year old it's not the earliest time to start, especially since she can probably eat solids.
I would start from the beginning:
-Get her used to eat from the bottle. You can put pumped milk in the bottle.
-Add some taste to it and see how she reacts. Add more if she doesn't complain. Carrot is a good vegetable to start. (Cut in small cubes, cook to make it soft, put in the mixer with some water until you get a carrot juice with no pieces)
-Alternate with other vegetables. (avoid vegetables with a strong taste like cabbage, and put as little potatoes as possible. Don't use mushrooms)
-Occasionally let her try some solid with a spoon
It needs to be progressive and you will probably need to find some stratagems:
You say she accepts only breastfeeding. Try to let her mother breastfeed and alternate with the bottle every 1 or 2 minutes, discreetly. (everyday, progressively without forcing her) The mother needs to give her the bottle at first.
Eliminate all source of stress during feeding time. No big noise, no angry parents, no impatience...etc.
You can also teach her how to hold the bottle and put it in the mouth (if she doesn't know already) tell her she's a big girl and she can eat alone like dad and mom. Maybe show her how good it is and drink from it?
She's not going to take the habit the first few days, so no impatience, no worries or stress. Just let her know there's the bottle during feeding times.