I used a program back in the day called RAM Doubler for my Mac. It just used virtual memory (storage space on the hard drive) to "increase" the RAM. Nowadays, computers can have up to 128 GB of RAM, depending on the model. I know the discontinued iMac Pro could hold 128 GB of RAM, if I recall correctly. So, there isn't a need for these types of programs anymore. Even if they worked, which I doubt, you still need to increase RAM physically anyway once it is required. This would depend on the applications and the OS, and their memory requirements.