"Donate" sounds strange, but yes, you can pay any bill from any account – including your personal one, or cash in your wallet. Technically, this would be regarded as a loan to the company, and you can later pay it back to yourself. As long as it's a business-related expense and the company's name is on the bill (above a certain threshold), you can claim those expenses on the business' taxes if you later make any revenue.

What may make this a bit complicated (and make the advice given above sound) is that one of the condition triggering bankruptcy is having more liabilities than assets. If you start the company with 1 Euro, and then go for coffee with the notary spending 10 Euros with the intent to claim it as a business expense, you're 9 Euros underwater. Not sure if this is something you have to monitor throughout the year or if it only becomes relevant when you actually do the bookkeeping at the end of the year.

Contrary to popular opinion (and the article) this stuff is quite easy to sort out as long as it doesn't involve real money, so I wouldn't worry about it. I know some people start companies with a bit of money for this reason, or even use something physical (i. e. their notebook) as an initial deposit into the company.

And just in case people are wondering "but why": these rules are supposed to protect vendors. Limited liability companies shield the founders from financial responsibility, so the rules are written in such a way that founders/owners are on the hook for at least 25,000 Euro (GmbH), or – nowadays – that the risk is clearly communicated to vendors. You can start a personal company much easier (basically a form with an address field and three questions) if you don't need limited liability.