The safest way to access Proteus Professional for free is through the official Labcenter Electronics Free Trial page.

: There is a 14-day limit on microcontroller simulation for your own designs.

Proteus Professional 2020 is a comprehensive software suite developed by Labcenter Electronics for electronic design automation, specifically circuit simulation, schematic capture, and PCB layout. While the full professional version requires a paid license, a is available for evaluation. Free Download & Installation