You don't have to look too far to see the impact of fintech, or financial technology, on your life. It powers your mobile wallet, allows you to pay your bills online, and enables you to trade stocks from the palm of your hand.

It was the reason you were able to shop from home under lockdown, and why so many merchants were able to keep their businesses open.

This is just the beginning for fintech, and as the saying goes, 80% of future growth products haven't been created yet. But you can buy in to amazing companies that are innovating today and benefit from their enormous growth opportunities. PayPal Holdings (NASDAQ:PYPL), Square (NYSE:SQ), and MercadoLibre (NASDAQ:MELI) are all fintech stocks that I would buy right now.

A woman paying with a mobile phone.

Image source: Getty Images.

1. PayPal: The past, present, and future of fintech

PayPal is busy working on a fintech ecosystem that provides everything a merchant or individual would need in the world of digital payments, and it wouldn't be surprising to see it get there. It already offers a large suite of features, recently adding buy now, pay later for shoppers and cryptocurrency trading for Venmo accounts.

Despite its status as the oldest fintech on this list, 2020 was the company's best year on record. Revenue increased 22% year over year, and net new active accounts grew 95% to 377 million. It's expecting a 19% sales increase in 2021. It's unusual to find a merchant that doesn't accept PayPal, and it's truly a ubiquitous presence in e-commerce.

The company envisions a lot more growth ahead. It sees a $110 trillion total addressable market, leaning into newer areas like asset trading, business-to-business, and physical retail, and it expects to more than double 2020 revenue to $50 billion by 2025.

PayPal stock gained 130% over the past year, and investors can expect a lot more in the near and long term.

2. Square: Cryptocurrency leading the way

Square operates two fintech ecosystems, one focused on small business solutions, and the other, Cash App, on personal accounts. Cash App has become way more than a simple peer-to-peer payments network, newly offering stock and cryptocurrency trading as well as some banking features.

Cryptocurrency has become a big deal in the past few months, as its price has soared and more people are getting in on the action. Tesla's Elon Musk has been loudly advocating Dogecoin on Twitter, and even JPMorgan Chase is creating a fund with it. 

A man paying on his computer.

Image source: Getty Images.

Cash App, and specifically cryptocurrency trading, has been the real story recently for Square. Cash App revenue increased 502% year over year in the fourth quarter, but without Bitcoin trading, it was 127%. That's still impressive, and between the trend toward increased digital payments and new features, Cash App has a long runway toward growth. 

Square also bought more than $200 million of Bitcoin recently, demonstrating its confidence in cryptocurrency as a standard form of currency. 

Square stock was a winner during the pandemic and has been an amazing growth stock, gaining more than 300% over the past year and nearly 1,700% over the past five years. But in many ways, it's just getting started.

3. MercadoLibre: Bringing fintech to Latin America

MercadoLibre is a the Latin American answer to PayPal and Square. It offers merchant and small business solutions as well as a digital payment platform, Mercado Pago.

The fourth quarter was another solid one, with a 149% year-over-year increase in sales (currency neutral) and a 71% increase in users, up to 74 million, and 132 million for the full year 2020. Gross merchandise volume increased 110%, and total payment volume grew 134%.

While the numbers look pretty good, you should consider MercadoLibre because of its potential. It operates in 18 countries, but most of its revenue comes from just three -- its home base of Argentina, the largest South American company, Brazil, and Mexico. 

According to e-Marketer, this is the fastest-growing region for e-commerce. Brazil itself has over 200 million people, and digital payments are still a a fraction of the total in these areas, making it an optimal spot to grow. With its multi-country penetration, MercadoLibre has been able to scale its operations to gain greater value and provide more competitive services. 

The stock gained 184% over the past year, and with the company's enormous opportunity comes a great growth opportunity for investors.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.