The first step here is getting everything out of the cloud that is in the cloud. The best way is to download your photos and videos to a computer hard drive. With iCloud, this is done automatically in Photos on macOS (just make sure Download Originals to This Mac is enabled under iCloud in the app settings), and you can also use iCloud for Windows to do it on Windows. For Google Photos, head to Google Takeout to download everything.
You can turn off the automatic iCloud backup of your photos and videos on an iPhone by heading to Settings, tapping your name at the top, and then iCloud and Photos. There's a similar option in the settings for Photos on macOS. In the Google Photos mobile app, you can tap your profile picture (top right) then choose Photos settings and Backup, and disable the Backup option. best way to store videos from phone
This then leaves you with the question of how to get any new photos and videos you take on your phone off your device and onto your computer, where they can join everything you've just downloaded from the cloud. If these files are only stored on your mobile device, they'll all be lost if something should happen to your smartphone, so you want to transfer them regularly.
An old-fashioned USB cable will do the trick rather well. You can plug your iPhone directly into a computer and then use Finder or Photos (on a Mac) File Explorer or the native Photos app (on Windows) to transfer files across. The process is the same as moving any other files around on your system, and once these copies have been created, you can free up space on your phone (if you need to) by deleting the originals.
A syncing app such as Dropbox will move photos and videos from your smartphone to a desktop computer wirelessly, but you'll then need to move them out of the Dropbox folder on your Mac or PC—otherwise, you'll quickly fill up your free allocation of storage and be back in a position where your photos and videos are stored on servers in the cloud rather than your hardware.
There are specific software tools available too. The Phone Link Windows app that Microsoft develops is good for transferring photos and videos from a connected iPhone or Android phone, while MacDroid (which will set you back $20 a year after the free trial) makes it easier to move files from an Android device to a Mac.