How do you create and share a Video from a Slideshow created in your phones on an iPhone?

Salutations gbird_60, 

That doesn’t appear to be an option for a curated Memory in the Photos app. You can share the Photos or you can add music without copyright to the memory. You can also take the photos from the memory and create your own slideshow by either finding the photos within the app and creating one or selecting the photos from the memory when it shows them to you below the memory and saving them to an album, then creating a slideshow with them. 

Your post suggests you’re using an iPhone, so the following link goes over how to do that - Watch memories in Photos on iPhone 

Share photos from a memory

You can share multiple or individual photos from a memory.

1. Tap a memory to play it.

2. While the memory plays, tap the screen, then tap .

3. Tap , tap Select, then tap the photos you want to share.

4. Tap , then choose how you want to share.

Thanks.