The Internal Drive of this computer has a Finite Capacity >> " 245GB of storage "
" I keep getting storage full messages " from the computer means.
You can not cram any more stuff and or can not save any changes to files you are working on.
The Drive is Full - full stop
Not to scare you but if not attended to right away
The machine may only boot up in Safe Mode
Or worse, cease to boot up at all.
It’s good computer practice to keep at least 15% to 20% of the total drive capacity empty to avoid unintended consequences.
Purgeable Space is controlled by the operating system. When the system needs more empty space, it moves some purgeable space to empty space.
There’s no user action to hasten this transition. It can take days or longer.
The links below help identify what’s taking up space on the internal drive and provide ways to remove user-controlled data (Home Folder).
Rebuild the Spotlight index on your Mac.
What is “Other” storage on a Mac, and how can I clean it?
GrandPerspective
How to delete Time Machine snapshots on your Mac.
This often occurs if the Time Machine Drive isn’t attached to the computer and TM Backup is set to run on a schedule.
TM Backup makes snapshots on the internal drive until the Time Machine Drive is attached. Then, the snapshots are transferred to the external drive.
View APFS snapshots in Disk Utility on Mac
See used and available storage space on your Mac.
Locate backups of your iPhone, iPad, and iPod touch.
Delete a user or group on Mac
If you have had another user account on the machine and have since deleted it
But have left the User Account Folder of that account intact - this too will use up space on the computer