Some days my baby has soft poop other days hard. should i be concerned or does this have to do with what she has eaten that day?

Food related: Yes, this is likely related to the food she had.

Foods influence poo: The average transit time for processing food into poo varies somewhat with the food ingested. If u want to slow baby down or firm them up a steady diet of applesauce, rice cereal & bananas will do the trick. If you want to spead them up fruits, (peaches, pears etc.) & juices will help.There is a bit of a lag time between feeding & effect depending on the kids situation.