Hello. welcome to HCM.
an 11 month old child with only 6 kgs is definitely underweight
and infection are two common problems which a child faces during and after introduction of solid foods.
You must plan her diet such that she has at least two helpings of fresh well washed mashed fruits daily inbetween meals.
Her diet can be anything- rice or wheat which is your staple diet. make sure to mix it with adequate amount of pulses. The Indian khichdi is a good choice for many parents. you can pressure cook it with added clean vegetables like carrots, beans, spinach and tomato. This meal should be given at least twice a day. Once you can give her a commercially available baby food
if she likes taste. Inbetween, milk should be given on demand. You can also attract her with nutritious biscuits, aas child of this age wants to eat themselves.The calorie intake must approximately be 100 calories/ kg/ day.
You can give supplemental micronutrient
syrup as directed by pediatrician
Make sure, cleanliness is given utmost importance while feeding child