Personal Experience

No matter how high-end the company you work for is, always remember to keep a copy of your labor contract. Don’t lose it—if you don’t have one, get it as soon as possible, and keep it safe.
If later the company encounters problems, or if there are issues with your salary, this will be your biggest safeguard.
I personally have been working, and even in the 21st century, I’ve never cared about labor contracts or taken them seriously. Last year, a company I worked for had problems with how it was run and owed me wages. It wasn’t a tiny amount and it wasn’t a huge amount either—15W.
The boss tried to look for loopholes and use the labor contract to make things difficult. Luckily, I kept call records, work screenshots, and social security records, and I also made several trips to submit the documents.
I strongly advise everyone to make sure they keep their labor contract. This is truly the only guarantee for your work. Ideally, you’ll never run into trouble—but just in case, future disputes are your ace in the hole.