Okay, so imagine you have a toy box that has a lock on it. You are the only one who has the key to open the lock and play with your toys. This means that nobody else can access your toys without your permission.
Forced-access regulation is kind of like a grown-up version of this toy box scenario. Some big companies have a lot of important information or resources that they don't want anyone else to have access to without their permission. In order to keep this stuff safe, they might put a "lock" on it, like a password or a security code.
But sometimes, the government or other outside organizations might really need to see what's inside the locked box. This could be because they suspect the company is hiding something illegal or dangerous, or because the information/resources in the box could be really important to public safety or wellbeing.
So, forced-access regulation means that the government or other organizations can legally force the company to give them access to the locked box. It's kind of like having a special master key that can open any lock, even if the owner of that lock doesn't want it to be opened.
This is a controversial topic because some people believe that it's important for companies to have complete control over their own information and resources, while others believe that the public interest should take priority over a company's private interests.