how do i get more storage

What is “Other” storage on a Mac, and how can I clean it out?

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The final word from Apple on Managing the " Other/ System Data “ Category

Other / System Data: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.

As suggested above, external storage can be increased by purchasing an external SSD or hard disk drive.

OWC/Macsales is often recommended here as a provider of Mac compatible accessories.

Also, if you need it, additional iCloud storage can be purchased by subscription directly from Apple.

Please see > Upgrade to iCloud+ - Apple Support

iCloud+ storage can be upgraded, downgraded or cancelled at any time.

You can try this: Free up storage space on your Mac - Apple Support

Or, you can buy an external drive.