Can I download my digital games onto external hard drive

So I did further investigation lol and learned that i don't have the digital version but the disc one. The missions that I deleted were the missions that come with the disc. So I have unplugged my external hard drive and am attempting to install the game
onto the xbox hard drive. If this works is there any way I can transfer my saved games from my external hard drive to the xbox hard drive?

Yes I have also bought an external hard drive.

I downloaded the games onto that hard drive.

As denis said, the external drive must be attached to your Xbox One and part of it's internal storage pool. Once an external drive is set for game storage on Xbox it will ignore any file it didn't place there.

Set you external hard drive as default location in the settings, and every game will be installed there by default no matter whether install was triggered manually or from PC or mobile.

To do so, follow these steps:

1. Go to Settings on your Xbox

2. On Settings page, go to System, and then select Storage

3. There, on the right you'll see all the drives including your external drive.

4. Select your external drive where you want to install games, and press A button on controller.

5. This will open the menu. Here select the option "Install here by default".

Then to install games from PC or mobile, you will have to trigger the installation remotely. To do so

1 .Open Microsoft store App, or use Xbox.com

2. Find the game that you own and want to install.

3. There click Install button and you'll be prompted to select a device where to install. Select your Xbox One and proceed.

Yes you can it unders setting/ storage