Investing in the share market is one of the most reliable ways to build long-term wealth, but not all investments are created equal.

For those seeking simplicity and consistency, exchange-traded funds (ETFs) offer an excellent solution.

Unlike individual stocks, which require careful analysis and ongoing monitoring, ETFs provide diversified exposure to a wide range of assets. This reduces risk and makes them ideal for hands-off investors.

Fortunately for Aussie investors, the ASX is home to many high-quality ETFs that are perfectly suited for a buy-and-hold strategy.

Let's take a look at three ASX ETFs that could be great options for investors looking to buy and hold for the next 20 years. They are as follows:

BetaShares Diversified All Growth ETF (ASX: DHHF)

The BetaShares Diversified All Growth ETF could be a top ASX ETF to buy and hold for the long term. Especially if you're a fan of growth shares.

It was named by BetaShares as a top pick for investors. The ETF provides investors with access to a globally diversified portfolio of approximately 8,000 stocks. These holdings cover large, mid, and small-cap companies across Australia, the US, and globally.

Betashares notes that this offer "investors exposure to an 'all-cap, all-world' share portfolio with the potential for high growth over the long term."

iShares S&P 500 ETF (ASX: IVV)

Another great long term option for investors could be the iShares S&P 500 ETF.

This fund is home to 500 of the largest companies on Wall Street. These are from all corners of the share market, which means you get plenty of tech exposure but also other industries such as consumer staples and mining.

Among its holdings are the likes of Alphabet (NASDAQ: GOOG), Apple (NASDAQ: AAPL), Exxon Mobil (NYSE: XOM), McDonald's (NYSE: MCD), Microsoft (NASDAQ: MSFT), Nvidia (NASDAQ: NVDA), Starbucks (NASDAQ: SBUX), and Walmart (NYSE: WMT).

Betashares Global Quality Leaders ETF (ASX: QLTY)

Finally, a third option for investors to look at as a buy and hold investment is the Betashares Global Quality Leaders ETF.

When investing into the share market, it's always a good idea to put your money into the highest quality companies you can find.

But rather than having to find out which shares are high quality, investors can just trust Betashares to do it for them. The fund manager, which recently recommended this ETF, has pulled together around 150 of the highest quality companies from across the globe into a single vehicle.

Among its holdings are the likes of Visa (NYSE: V), Costco (NASDAQ: COST), and Accenture (NYSE: ACN).