i am updating my device by itunes but its showing that i dont have enough space in the disk that i am downloading update
iPhone 13, iOS 16
Question marked as
Then you need to move or delete enough files from the Mac so you have enough free storage space to download the update. Start by making sure you have emptied the Trash. The next best place to look for stuff to mover or delete is in the Downloads folder.
Free up storage space on your Mac - Apple Support
You need to make sure you always have at least 20GB+ free on the boot drive or bad things can happen to your data on the boot drive (data is corrupted, or perhaps the data is inaccessible because it is impossible to delete items from an APFS volume if there is no free space left).
It appears your Mac has only a 120GB boot drive which is very small. It only has enough room for the OS, apps, and a bit of personal data especially if you leave 20GB - 30GB of free space available.
Make sure you have a good backup before doing anything in case you accidentally delete something important.