the storage on my MacBook Air Early 2014 is nearly full and I am having difficulty working. I need to install new applications but my start up storage is nearly full. Can I use my iCloud to download new apps and back up my files?
I think you might be confusing your hard drive storage on your laptop with the cloud storage iCloud. If your laptop is running out of space, then you may want to consider getting an external backup drive for your needs.
To answer your question, no you can't use iCloud to "download new apps and back up" your files.
You may want to also consider using Time Machine -- Use Time Machine to back up or restore your Mac - Apple Support
can I use icloud to store non-apple apps?
