any advice to stop my puppy being scared of people whenever i take her out

The best thing I've found is to ignore scared behaviour. Don't try to comfort or reassure her as she will think you are praising her for being scared. Only let her have attention from strangers when she isn't acting scared - if she is cowering away from them they (and you) must ignore her completely - don't even look at her. It takes some time, but if she learns that people go away anyway she'll start to accept them. Good luck.

Thank you, I will try this. Do you have any advice on a dog that barks at dogs when we are out, but never ever at class. (Even if we meet the same people and dogs)

How old is your dog...some dogs go through a 'fear' stage at about 5-9 months....would he fit this age group?
I would take some nice tasty treats when you go out and when he barks give him the sit command and when he sits and looks at you praise and treat.Then carry on your walk and repeat as necessary
Archer