The iphone4s does not have a software update function under general in the settings and I want to update the iOS, what's going on???

your title says iphone 4s and in your post you talk about iPad air. Which one is it?

If your iPad is disabled because of too many attempts to enter the passcode, http://support.apple.com/kb/HT1212 will help you resolve this.

For your iPhone 4s issue - the "over the air" update facility was introduced in iOS 5 or 6 (can't recall which exactly but one of the two), your device info indicates you're running iOS 4.3.x, is that correct? If so you won't have a "Software Update" button in Settings/General.

Prior to the introduction of over the air updates you had to update iOS by plugging the device into a Mac or PC running iTunes (this method is still available in iOS 7 too btw, it's often the best way to install major updates).

OTA started with iOS 5.