Upgrading OS on an old MacBook Pro

I have a 2009 MacBook Pro OS El Capitan 10.11.4 and it cannot be upgraded to Catalina. How can I update to (at least) 10.12.1 or higher so that I can meet the minimum requirements of certain apps? (The computer has 8GB (2 x 4GB) of 1333 MHz DDR3, which was the maximum memory at the time.)