Yes it is safe to delete everything from the SoftwareDistribution folder, it is probably best to use Disk Cleanup to do that, but either way no harm will come ...
This is a PowerShell script to the Clear the Windows Update Cache. The Windows Update Cache is a special folder that stores the update installation files.
Way 1: Clear Windows Update Cache via File Explorer Step 1: Type File Explorer in the Search box to open it. Step 2: Find and right-click Local Disk (C) to choose Properties. Step 3: Then, click Disk Clean-up. After that, click the Clean up system