phone storage is full with out any reason

Hi @binyam75245

Open the My Files app and tap Analyze Storage to find out what files are being stored and what they are e.g. pictures, videos, download files apps etc and whether they're your files or not

If you can't delete enough unnecessary files, perhaps download and install and run an anti malware app (example only) to check if there's any malware installed on the phone that may be downloading in the background unbeknownst to you.

After this, to limit the amount of downloading occurring, activate the data saver setting so that there's no data access i.e. no internet access unless you want it to happen. Go to Settings > Connections → Data usage → Data saver and tap the switch to activate it. When the data saver feature is activated, an icon will appear on the status bar.

Note : The data saver feature if activated, doesn't affect phone calls or sms messages (plain text messages) but it will stop the send/receive of mms messages (texts with pictures/videos), just that you're aware of this if you use mms a lot.

If you're simply running out of legitimate storage space, what size micro SD card is inserted in the phone? The phone supports up to a 512GB micro SD card if you need more storage.