You generally cannot invest in the IPO, as an individual investor. The offering goes through the investment banks running the books, and from them through to full service brokers that sign up to buy X shares at Y price, through their customers or directly.
To try, you can call Vanguard and ask if you can buy shares. They probably aren't participating.
The best you can do is to buy on opening day, or if it really pops, wait for the first good drop. This could happen at the first earnings call, or with some macro event like Covid. But you can also set an alarm for 180 days after the first day of trading, when restricted shares can trade. There is often a drop as long holders and employees look to cash in some pre-IPO shares.
There are some sites that trade in private shares, but you generally have to be an accredited investor (read: already have a big investment portfolio) to participate.
The other option is to look at SPACs. These blank-check companies do trade publicly ahead of a merger with a private operating company--Another way to IPO. I am having a great experience with Luminar, which will begin trading as LAZR tomorrow. (The SPAC was GMHI) The SPAC route is faster and cheaper than a regular IPO, and for good reason--There is less regulation and oversight of them. So, they also can attract riskier / sketchier companies. So, you need to know enough to do your own due diligence. The proxy statement on Luminar was more than 1 inch thick--prob. 600 pages, with exhibits. But, It's a way in.
