Want to invest in stocks that you can buy and forget about? If so, you'll want to consider companies with plenty of long-term growth opportunities and solid financials. Among the best growth investments that check off those boxes today are Novartis (NVS -0.58%), Visa (V 0.14%), and Microsoft (MSFT 0.13%).

These are unstoppable businesses that are sure to get bigger in the years to come. Let's find out a bit more about these three buy-and-hold candidates.

1. Novartis

Swiss pharmaceutical giant Novartis is an excellent example of a stable, long-term investment to hang on to. The company recently spun off its generics business, Sandoz, so that it can focus more on long-term growth opportunities. Novartis' strategy involves being a "pure-play innovative medicines business" focusing on five therapeutic areas: cardiovascular, immunology, neuroscience, solid tumors, and hematology.

The company generates strong margins that should improve as a result of its recent spinoff. Through the first half of 2023, its core innovative medicine business reported $8.5 billion in operating income, which made up 39% of the $21.8 billion in revenue it generated. By comparison, Sandoz posted an operating profit of $933 million, or only 20% of the $4.8 billion in revenue it brought in.

Novartis makes fantastic margins and they are going to get better due to the company focusing on its more profitable operations. As of the end of the second quarter (which ended in June), the drugmaker had 129 ongoing projects in its innovative medicines business, with 50 of them being in phase 3 trials or later (i.e., in the registration process). With plenty of growth opportunities still out there for the company and Novartis also offering a 3.6% dividend yield, this is a terrific growth stock for investors to buy and hold for decades. 

2. Visa

Credit card company Visa is another solid stock to hang onto for the long haul. What's great about the business is that it can do well regardless of how strong the economy is. Even in a downturn, consumers still need to spend money, and if they don't have access to much of it, they may turn to credit cards more than usual. And in good economic times, consumers are also spending, with credit cards being an attractive option versus cash for the perks and safety that they can offer.

Visa is also investing in future growth opportunities. Earlier this month, it announced a $100 million initiative to invest in generative artificial intelligence (AI). AI has the potential to improve the business, including making Visa's operations more efficient and safer, while also paving the way for new products for consumers and businesses.

The company already has hugely successful operations, with Visa reporting $16.5 billion in profit over the trailing 12 months on revenue of $31.8 billion. With profit margins of more than 50%, this is a business that gushes cash. Visa is an industry leader and it's hard to see that changing anytime soon. This is a stock investors should feel comfortable holding for decades because it has strong financials and is likely to grow along with the economy.

3. Microsoft

The third stock to round out this list is Microsoft, and it's no slouch in the growth department, either. The company recently wrapped up its acquisition of video game giant Activision Blizzard, which is sure to create new growth opportunities for Microsoft. Already the maker of a top console in the Xbox, it now also owns the popular Call of Duty series. Between expanding its gaming business and launching new AI-powered office products, Microsoft has some exciting growth opportunities to pursue in the future.

The company is worth a mammoth $2.4 trillion, and its value is only going to get bigger over the years as it bolsters its operations through potentially even more investments and acquisitions. It won't be difficult for Microsoft to continue to do so because it makes tons of money. Over the trailing 12 months, it has brought in $211.9 billion in revenue, and $72.4 billion of that has been profit, for an impressive net margin of 34%. This is an ideal stock for buy-and-hold investors, as Microsoft is not only an industry leader, but it remains focused on unlocking new growth opportunities.