In the US you can run a business as a sole proprietorship. Sign up for Stripe and start selling subscriptions to test things out. You should probably check in

In the US you can run a business as a sole proprietorship. Sign up for Stripe and start selling subscriptions to test things out. You should probably check in to sales tax in the US and Europe that you might be responsible for. Checkout TaxJar. In the beginning this is less critical as most have minimums that apply, but worth checking in to. Once you have revenue you can form an LLC or other entity.