If you live with or work with millennials, you know one thing about them: They never carry cash. Make a lunch run for them, and they may ask you, “Can I Venmo you my share?” Huh?

You might not even know what Venmo is, let alone how to use it. Well, it’s time to learn about person-to-person, a.k.a. peer-to-peer (P2P), payment apps.

That’s why we’re going to tell you about mobile pay apps and how to safely use them.

What are P2P apps?

Carrying less cash in our pockets isn’t a new thing. Years ago, banks introduced the debit card and many who made the switch loved it.

And the trend of a being cashless appears to be growing. U.S. Bank conducted a survey recently and found people are carrying less cash than in the past. Around 50% of respondents said when they go out, they bring cash less than half the time. When they do have cash, over 75% said it’s less than $50.

Now, technology and mobile devices are helping the cashless movement progress. Researchers at NerdWallet said what’s driving this cashless trend is the popularity of P2P apps.

So, what are they?

The concept is pretty basic, honestly. It’s a way to send money to a friend through a mobile device. P2P apps let you transfer money from your bank account or credit card to another person’s account.

People use them to split the bill at dinner, the cost of a ride-share like Uber, or transfer $5 for the coffee someone picked up on the way to work. It’s so much easier than carrying cash and having the correct change.

The question is, are P2P apps safe?

The answer is a little tricky. For the most part, they are safe.

However, like most things these days, there are some risks to be aware of and steps you need to take to protect yourself. Here are a few things to watch for.

Hackers can rip you off

Of course, the common cybercriminal can always cause havoc. If a hacker gets into your account, they can bleed it dry.

That’s why many of the popular P2P apps have two-factor authentication (2FA) as a security option. We always recommend taking advantage of it when available to protect online accounts from thieves.

P2P apps: Phishing attacks could trip you up

This is a common mistake that anyone could make. If someone sends you money through a P2P app, you’re going to receive a notification.

For example, you might get an email letting you know that someone has sent you money. To retrieve the money, you can click on a link inside the email. You see where this is going?

Yep, scammers can spoof emails to make them look like it’s an official notification that you have money waiting to be collected.

That’s why if someone sends you money, before clicking on a link inside the notification, always call the person to make sure it’s real. If an email claims your sister sent you $30, call her to verify that she did. She can give you the details so you know it’s safe, like which P2P she used and how much was sent.

Only send money to people you know

OK, pay attention here. Many of the P2P apps are intended for transfers between friends and family and should not be used to make purchases from companies or online marketplaces.

In fact, Venmo specifically says using it to send or receive payments for goods or services violates its terms. Your transfer will not be protected if you violate the user agreement.

There have been several reports of situations like this lately. A Brooklyn native recently told “Consumer Reports” about his nightmare scenario.

What happened was that the man listed a high-end camera for sale on an online marketplace. Someone ended up buying the camera for $1,100 and asked if he could pay through Venmo.

The seller accepted the Venmo payment and handed over the camera. A few days later, he received an email from Venmo saying it suspected the deal breached its no-commercial-use terms and had reversed the transaction.

Here’s where it really gets messed up. The buyer completely disappeared and wouldn’t respond to texts, emails or phone calls. He ended up getting his money back and kept the camera. The seller was just out of luck.

Don’t let this happen to you. Never send money to people you don’t know for things like concert tickets, or expensive goods that might breach the P2P’s terms.

Also, make sure you’re typing in the correct email address or phone number of the friend you’re sending money to. If you initiate a transaction and wind up sending it to the wrong person, most P2P apps won’t help you get your money back. You’ll be left hoping the stranger you just paid is an honorable person and will agree to pay you back. Good luck with that.

Now that some potential hazards are out of the way, let’s look at a few of the more popular apps.

Popular P2P payment services

P2P apps: Venmo

If you’re dealing with a Millennial, there’s a good chance Venmo is the P2P app they are using. It’s actually owned by PayPal, which is another type of payment system that’s been around since the ’90s. And that actually factors into the way you can use Venmo.

As we said earlier, Venmo’s User Agreement doesn’t allow for purchases of goods or services from people you don’t know. This is probably the biggest drawback to using Venmo, the lack of protections on transfers like this. If you don’t violate the User Agreement, you shouldn’t have a problem.

The good news is, you may use Venmo for goods or services at participating businesses. One way to tell is if you see the PayPal button as a payment option.

Not all places that accept PayPal accept Venmo. But there’s a chance.

Simply tap the PayPal button on to launch the PayPal checkout experience. If Venmo is accepted, a Venmo payment option will appear on the next page. You might even see a Venmo payment option in a merchant app or mobile website during checkout.

As far as security, Venmo rings the bell. It does offer two-factor authentication, which you should definitely take advantage of.

Venmo is available on both Apple and Android. Click here for Apple. Click here for Android.

P2P apps : Zelle

Since P2P apps have been growing in popularity, banks wanted to get in on the action. In 2017, Zelle was launched.

It’s run by Early Warning Services and is built directly into many banks’ mobile apps to make it easy for customers to use. You might already have access to it and not even know.

(Note: Click or tap here to see if Zelle is included in your bank’s app.)

In addition, Zelle partnered with banks and credit unions across the country to offer an easy way to transfer money to friends and family. If it isn’t already built into your financial institution’s app, you can download the Zelle app.

Here’s the proble