To automatically save content from your Android phone to Google Drive, you can set up your phone to back up your files:

• Open your phone's Settings app
• Select Google
• Select Backup
• If this is your first time, follow the on-screen instructions to turn on backup
• Select the data you want to back up, such as photos, videos, or device data
  

You can also back up your content, data, and settings from an old phone to Google Drive on a new phone:

• Sign in to your Google Account on your new phone
• On your old phone, swipe up from the bottom of your screen to manage your backups
• Open the Google Drive app
• Tap Menu
• Tap Backups
• Review the details of backing up your phone with Google One
• Tap Turn on
• To back up your info in the background, tap Back up now

You can access your saved photos and videos from any device you're signed into, but only you can find them unless you choose to share them.