How to clear space on my Mac when storage is almost full?

Check where the space is being used and see if anything you can clean up otherwise as @kaz-k suggests you need to move personal data to external drive. As an example if you use Apple Music perhaps you have a lot of downloads; Photos library can grow etc. There are options to 'optimize space' on the Mac for cloud data sync'ing to your local Mac if you don't have space. Anyway first step is to see where the space is being consumed if this utilization is not expected. If you go your home directory in Finder then View > Show View Options and check on "Show Library Folder" and "Calculate all sizes" that will give you a quick handle where space is being used in your home directory etc. Also go to System Settings > General > Storage and there should be a chart of how the space is being used.

Have a look at > Free up storage space on Mac - Apple Support

Hi,

Try to move data from internal drive to external one if you have external drive.

If you are using Time Machine, you can see if there are any snapshots to remove.

finder showing incorrect figure for used … - Apple Community

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