There are a lot of platforms nowadays having their staking feature but with this still, invested your assets on their platform and there's some contract on it like you cannot withdraw those funds into for a week or months. Still, it's better to make a background check because staking still it's an investment with interest it's catchy right but still they have the rights to get those assets.
Yes, that's their contract for locking your funds on their platform.
But there are the platforms that also allows you to freely move in and out your funds from staking it from them. If you're for the flexi, you might just use a wallet instead of any exchange that you have no control over your funds.