We are going to one day long trip with 6month starting baby. What are the items are keep in bag?

If baby is breast feeding then life is super simple. All you need is change of clothes diapers blanket an extra sheet for baby to lie on and wipes to clean the baby. Add a few napkins to help wipe the face etc. If baby is eating food from outside or taking formula then you will need to be more elaborate. Carry the required nos of sterilised bottles and teats as you will not be able to sterilise items there. Carry boiled and cooled water to mix the formula. Carry the formula container with the powder in an airtight or lock lock container to avoid spillage. Additionally all the other items mentioned above. For trips it is also recommended that both parents carry an extra change of clothes as well since baby may spit up or throw up and you need to change your clothes too. Have fun.