Investors can find great investment ideas by identifying rapidly growing companies that are disrupting old ways of doing things. All it takes is one winner to positively impact your financial goals. Three innovative fast-growers to consider are DocuSign (DOCU 2.46%), Roblox (RBLX 3.56%), and NVIDIA (NVDA 4.00%).

Let's take a closer look at why these stocks could have big upsides over the long term.

1. DocuSign: Paper contracts are moving to the cloud

DocuSign is taking the inefficiency and time-consuming process of dealing with paperwork out of contract management. By eliminating paper, DocuSign is significantly reducing the time to complete agreements and saving companies money in the process. 

Two office workers looking at a computer in a meeting room.

Image source: Getty Images.

DocuSign's eSignature product is a leader in this market. It's part of the Agreement Cloud platform, which offers advanced features to filter contracts by clauses and keywords using artificial intelligence (AI). This greatly speeds up the signing process. 

Management estimates the total addressable market for its services, where it generates revenue through subscriptions, at approximately $50 billion. This level is far above DocuSign's trailing-12-month revenue of $1.6 billion. 

The stock price has climbed roughly 500% since its IPO in 2018, and I would expect more gains over the next decade. Businesses are increasingly shifting to digital services coming out of the pandemic. DocuSign reported accelerating revenue growth of 49% in fiscal 2021. While management is forecasting 40% growth this year, DocuSign is still on track to grow its top line slightly faster than the rate posted before the pandemic.

What's more, DocuSign continues to see its customers expand their usage of its eSignature service. Spending from existing customers reached a record level in the fiscal first quarter, with the dollar-net retention rate reaching 125%. "From any vantage point, these are exceptional results that reflect the continued demand and engagement we are seeing from our customers across all industries and use cases," CEO Dan Springer said during the Q1 earnings call.

Management believes the trend toward digital agreement processes will accelerate going forward, which could make now a good time to buy shares. 

2. Roblox: The metaverse has arrived

For years, forward thinkers have envisioned the metaverse, a virtual world where people come to connect and share experiences. While Roblox is mainly viewed as a video game platform for kids, management sees the platform becoming much more over the long term.

Roblox was founded in 2004 and built with the vision that the platform would one day support billions of users. Recent financial results show it's headed in that direction. The platform currently has 42 million daily active users. Users are also highly engaged on the platform, buying virtual currency (Robux) to spend on additional content. This translated to revenue growth of 81% in 2020. 

Roblox is able to grow its user base quite rapidly because its platform is free to sign up for. Plus, it's accessible across a range of devices, including Microsoft's Xbox, PCs, virtual reality devices, and mobile devices. 

Roblox is working on expanding its demographic to older users. One way it is doing that is increasing the payouts to its developer community, which produces the content on the platform. While this might pressure near-term profits, Roblox should see the number of experiences increase, and therefore more growth in daily active users.

With growth accelerating during the pandemic, free cash flow also soared, reaching $518 million over the last four quarters. That's a healthy free cash flow margin of 22% compared to trailing bookings, and it provides a glimpse of how profitable Roblox could be over time. This level of free cash flow is impressive since the company hasn't even begun to really go after the lucrative advertising opportunities on its platform.

Roblox stock currently trades at a lofty valuation, so be prepared for volatility -- but the stock has tremendous upside over the long term.

3. NVIDIA: The chip stock behind major technological trends

NVIDIA is the leading graphics card provider in the world, with a commanding 81% market share of the add-in board market in the first quarter. Its chips are in most gaming PCs, and they also power every major cloud service provider. Because of this, NVIDIA is powering the services that people use every day, such as recommendation systems and speech recognition, as well as more advanced uses, including self-driving cars and medical imaging. 

NVIDIA's latest results show the business firing on cylinders right now. Revenue grew 84% year over year in the fiscal first quarter, and profits more than doubled. The stock trades at a high forward price-to-sales ratio of 22, but NVIDIA could still outperform as it continues to innovate.

For example, Daimler's Mercedes-Benz is working with NVIDIA to build the cars of the future. Mercedes is designing its future fleet to be completely upgradeable, with new software features that enhance the autonomous capabilities of the car. NVIDIA is also starting to license its own software platforms, such as NVIDIA Omniverse and NVIDIA AI Enterprise, which could be extremely lucrative to NVIDIA's bottom line.

"We continue to see uplift to our gross margin profile as our mix shifts to higher-value platforms," CFO Colette Kress said at NVIDIA's investor day in April. "Furthermore, software is a significant opportunity for NVIDIA. This revenue, as it scales, will provide an additional tailwind to gross margins."

This AI stock is well-positioned for growth. The future of computing is becoming more dependent on AI and data centers, and that's where NVIDIA is positioned extremely well with its advanced chip technology.