I lost all documents on my MacBook Pro Early 2013 a few months ago. I thought everything had back up to i cloud. Now I am trying to do my taxes but I need to transfer depreciation into from TurboTax 2015 to this year and I can not find it. It hope

See the "Restore specific files" section of the following: Use Time Machine to back up or restore your Mac - Apple Support

Also note that iCloud does not back up computers. It can be used to back up an iPhone/iPad/iPod touch. iCloud can also be used to sync files from a Mac but that is not a backup and any change made to the synced files (including accidental deletions) will be synced to iCloud.

iCloud is not a backup for Macs, only IOS devices.

Go to the time machine icon on the toolbar, click it and select 'enter time machine'