Yea im on W10 , but haven't received any notifications ( in fact i haven't touch any of the settings with in the xbox app , so it maybe turned off for some reason .If your friends are using party chat then they won't be heard through game chat, they will only be able to hear each other. The game and party invites should come in as notifications on the right hand side of the screen (I'm assuming you're using Win10), also you should be able to go to your friend's profile and join their party.
If you want to create a party and then invite people to it, when you open the Xbox app you'll see four tabs at the top right - Friends, Party, Messages and Notifications. If you click the second one (it looks like a figure with another person behind each shoulder) you have the option to start a party.
thanks john , i will take a look at this tomorrow , im off the bed just now , thanks for the info