Want to share a file wirelessly? There are dozens of methods to do so, from attaching it to an email to uploading it to social media . But not all of your options are equally secure. In fact, to keep prying eyes away from your data, we recommend that you send your file through a direct device-to-device connection.

Your phone and computer both come equipped with wireless transfer protocols that let you share files securely, sometimes without even revealing your phone number or email address. Each operating system—iOS, macOS, Android, and Windows—offers its own method. Here's how to take advantage of them.

For Apple devices

Your macOS computer and iOS phone can connect directly to other Apple devices via AirDrop. This type of link allows any Apple machine to send a file to another one, relying on Bluetooth to establish the connection and Wi-Fi to handle the data transfer. So for AirDrop to function, you must enable both Bluetooth and Wi-Fi—but you don't need to connect to an actual Wi-Fi network. In addition, this method of sharing is anonymous, which means you can send a file without knowing the recipient's email address or phone number—and without disclosing your own contact information to them. On the negative side, it only works when you're sending a file between two Apple devices.

Apple hardware enables AirDrop by default, but you can always double-check it. First, turn on your Bluetooth and Wi-Fi connections to ensure it will be able to function. Then, on macOS, open Finder and look for AirDrop in the column on the left. You should see a discovery option at the bottom of the window. For increased privacy, set it to Contacts Only , and for broader sharing, set it to Everyone . On iOS, open Settings > General > AirDrop , and again select either Contacts Only or Everyone .

Once you've enabled AirDrop, you can start sending data. When you highlight a file in Finder, open a picture in Photos, or launch a webpage in Safari, run your eye over the window until you see the Share button—it looks like a box with an arrow pointing up out of it. Click or tap that button and choose AirDrop from the menu. The system will detect any other AirDrop-enabled device within about 30 feet of your computer or phone. When the phone or computer you'd like to share with appears in the AirDrop window, select the device to start the transfer.

Before accessing the file, the recipient needs to approve the share. This is important because some people abuse the anonymity we mentioned earlier, using it to send obscene or obnoxious files to strangers. To prevent this from happening to you, either refuse to accept files when you don't know the recipient, or make sure to set your AirDrop discovery to Contacts Only .

What if you want to send a file to a friend's Android or Windows device? When you hit that Share button, you can pick a different option—such as an email or a file-syncing app like Dropbox —from the pop-up menu. However, these file-sharing methods do require that you have the recipient's contact information and that your phone or computer is connected to the internet. For example, say you use Dropbox on your iPhone. Choose a file you'd like to send to a friend, tap Share , and pick Dropbox from the menu. Next, choose a folder in your Dropbox, and the file will upload to that location. Finally, provide your friend's email address, and they will receive an email containing a link that they must click to download the file. This process is not quite as simple as AirDrop, but it can still get the job done.

For Android

If you want to send a file from your Android directly to another device, your best bet is to do so via a Bluetooth link, although you can also opt for near field communication (NFC). Bluetooth can transfer data around five times faster than NFC can, and it operates at greater distances too—the latest standard can share information between devices up to several hundred feet apart. That said, NFC sharing is more convenient, allowing you to send a file without pairing two devices; you simply tap them together. You may prefer NFC for sending smaller files between two Android smartphones. Although both protocols will let you send a file to another Android and neither can share with an Apple device, Bluetooth is the only one that lets you shoot your Android file to a Windows device.

Let's start with Bluetooth. On an Android device, go to Settings > Connected devices and toggle on the Bluetooth switch. Once it's enabled, open any app—from Google Photos to Twitter —and hit the Share button, which looks like three dots joined by a line. When the Bluetooth icon pops up, tap it, and Android will list any nearby Bluetooth-enabled devices—both Android and Windows—to which you can send that website or file. The receiving device may have to confirm the pairing action, but after that, the file will transfer easily.

To use NFC, your first step should be enabling it on both the sending and receiving devices. Go to Settings > Connected devices and enable NFC. (If it doesn't appear as an option in this menu, then you won't be able to use it.) From there, tap Connection preferences and turn on Android Beam . Now sharing is easy: Open any file or website on the screen, then tap the backs of the phones together. A sharing window will automatically pop up. Choose Transfer , and you're done.

For Windows

Windows devices, like Android ones, send files best over a Bluetooth connection. Although you can share Windows data over Bluetooth with other Windows devices and with Android ones, Apple machines won't accept a Bluetooth file transfer. If you want to make a Windows-to-Windows connection, you can also use a new protocol called Near Share, which works much like Apple's AirDrop.

First, as always, enable Bluetooth. On a Windows 10 machine, open the Start menu , click the cog icon to launch the main Settings pane, pick Devices > Bluetooth & other devices , and switch on Bluetooth . To actually share the file, you'll have to connect the sending device to the receiving one. From the same Bluetooth & other devices screen, hit Add Bluetooth or other device > Bluetooth to search for another Bluetooth-enabled Windows or Android machine. When the device you're looking for appears, tap or click it to connect. Now that your devices are successfully talking to each other, stay on the Bluetooth & other devices page and click Send or receive files via Bluetooth on the right side of the screen. Choose Send files , then the device you want to beam them to, and hit Next . On the subsequent screen, click Browse to search through your files, tap the one you want, and select Next once more to confirm.

Beyond Bluetooth, Windows 10 recently added another method for moving your files wireless between two Microsoft devices: Near Share. Like AirDrop, it combines Bluetooth and Wi-Fi to let you share files even without a web connection. Enable it by going to Settings > System > Shared Experiences and toggling on the Nearby Sharing switch. When you're ready to share a file, find it in File Explorer , right-click, and choose Share . (Alternatively, look for the Share button, which looks like an arrow pointing out of a box and appears in various places, including the toolbar of Microsoft Edge.) Finally, you'll see a list of Near Share-enabled Windows 10 devices. Pick a machine to share your file.