How can download all app from my iPhone to my new iPad air

You can’t transfer Apps from your iPhone to iPad. However, assuming that you are using the same AppleID, you can download and install all the Apps that are compatible with your iPad without having to pay again.

Any Apps that you purchase from the App Store are forever tied to the AppleID account from which the purchase is made - and can be installed on any of your compatible devices.

No, but you can download them from the app store though. Do check first: some developers only make apps that will work on the phone, but not on an iPad or vice versa.