There’s nothing worse than your iPhone running out of juice at an inopportune time. Starting in iOS 9, there’s a Low Power Mode that’s offered to you when the remaining battery charge drops below 20%, and it’s automatically disabled once the charge rises to 80%.

If you use AT&T, Verizon, T-Mobile, or Sprint in the United States with an iPhone 6 or newer model, you can turn on a feature starting in iOS 9 that enables your iPhone to send calls over a Wi-Fi network (and thus the Internet) rather than relying on spotty cellular coverage

If you regularly lose your pointer on big-screen Mac, Apple has added a feature you’ll like starting in OS X 10.11 El Capitan. Shake the mouse to and fro on your desk, or run your finger back and forth on the trackpad quickly, and the pointer expands briefly so you can find it.

You know that you can move the insertion point in text using your Mac’s arrow keys. But what you may not know is that the Mac offers several shortcuts that let you move around even faster. In most apps, hold down the Option key when using the left/right arrow keys to move left or right by a word. Use Command and the left/right arrow keys to jump to the beginning or end of the current line. Using Option and the up/down arrow keys moves the insertion point to the beginning or end of the current paragraph. And modifying the up/down arrow keys with Command takes you to the top or bottom of the entire document. Even better, add Shift to any of the above to select text from the current point to where you navigate to, so Shift-Option-Up arrow selects all the text from the insertion point to the beginning of the paragraph.

By now you’ve probably seen one of those odd-looking white squares with a bunch of smaller square dots that make up a random pattern inside—that’s a QR code. QR stands for “Quick Response,” and a QR code is a type of barcode, just like those you see on the packaging of nearly everything in grocery stores.

Passwords. Can’t live without ‘em, can’t remember more than a few. We’re all in the same boat, with numerous online accounts protected by passwords that we must enter repeatedly. Long ago, it might have been acceptable to have a single password that you augmented with a few numbers for your most important sites. Alas, that’s no longer even close to sufficient, now that the bad guys steal millions of passwords at a time, employ sophisticated hardware that can try over 350 billion passwords per second, and sell decrypted passwords on the black market. If you have a weak password on a site whose passwords are stolen, every other site on which you use the same password is vulnerable. That could result in your email account being used to send spam, or even having your online bank accounts drained. It’s dangerous out there.

There are oodles of ways to launch Mac apps. You can double-click an app in the Applications folder, click an app icon in the Dock, invoke Launchpad and click the desired app, or choose an app from the Apple menu’s Recent Items > Applications submenu. You can even add commonly used apps to the toolbar of Finder windows by Command-dragging them up there.