Your computer is low on memory- how do I fix

Generally speaking, here are a few things you can do to free up memory on your Mac:

Reduce the number of browser tabs and windows that you keep open.

Reduce the number of apps and documents that you have open simultaneously.

Restart you Mac more often - once a week is good.

And as @ku4hx alludes, it might be possible to increase the amount of RAM in your Mac, but thst will depend on the model and year of the machine.

Please post complete details as presented by "About This Mac" by clicking the Apple icon at upper left screen.

Depending on year, some machines have user replaceable RAM; some have soldered RAM and is not upgradable.

There may be ways to mitigate your situation, but details are needed. Do you have any known memory hogs for instance.

Are you running CleanMyMac? There have been several posts lately that CMM is falsely reporting low memory.

Other so-called "cleaning" apps may be doing the same thing as they compete with elegant self-maintenance routines your paid Apple to build into macOS. Macs, cat-like, clean themselves and have for over 20 years.