how do I clear caches from my mac desk top

Welcome!

The macOS runs automatic maintenance scripts during idle hours that take care of all the cleaning, clearing, and defragging one needs. It has worked that way for 20 years.

The only other action you can do is an occasional restart. I try to do that about once every week to 10 days. If you have very little RAM installed (4 to 8GB), more often may be better, like every 4-5 days.

Please DO NOT install any software that claims to clean, tune-up, optimize, mop, or change your Mac's nappies, as ALL those interfere with the automated protection and maintenance that you paid Apple to build into the operating system. I've seen far too many "poor performance" posts here that were traced to useless cleaning and anti-virus apps.

Are you having a specific problem that makes you feel the need to clear caches?

Boot into safe mode then reboot normally How to use safe mode on your Mac - Apple Support

1. To clear browser cache in Safari Click on the Safari drop-down menu and select Preferences.
2. Click the Advanced tab. Select the Show Develop menu in menu bar checkbox and close the Preferences window.
3. Select the Develop drop-down menu. Click Empty Cache.
4. Note: You may want to also clear your browser history.