Run the installer. You can continue to use it safely even after the trial period expires.
Below is a guide on the risks of preactivated software and the legitimate ways to use WinRAR. The Risks of "Preactivated" WinRAR
If you want a powerful, completely free, and open-source file archiver without any nag screens or security risks, consider these alternatives:
: After 40 days, WinRAR continues to function with full features. It will simply show a pop-up reminder to purchase a license when you open the application. One-Time Purchase
: A legitimate license is a one-time payment (not a subscription), providing peace of mind and supporting the developers at RARLAB. Safe Alternatives to WinRAR