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You could probably get an account with Interactive Brokers. Here's their list of available countries: https://www.interactivebrokers.com/en/index.php?f=7021

In New Zealand we also have https://www.hatchinvest.nz and https://www.sharesies.nz. You might have some similar services in your country.

Find a broker/platform in your country that lets you trade in the stock market they are listing on (if UK then IG and Hargreaves Lansdown are good), join, fill out the W-8BEN so you are able to buy US stock through the platform (they usually make this a 2 minute job) and then place an order when it’s live. You’ll be paying more than the true IPO price as the bank etc get preferential rates I believe but it’s as good as you’ll get

Try out Interactive Brokers. They seem to serve a lot of non-USA customers. Disclosure: A happy USA user.