playing a video in keynote on a PC

Keynote can't be played on Windows computers, the workaround is to export a PowerPoint file from Keynote

using File > Export > PowerPoint

Not all users of Windows have Powerpoint, to save purchasing Microsoft Office, Libra Office is a competent alternative, its free to any user.

Depending on version of macOS and thus version Keynote. I think there is a way to Share with intended person(s) even if they are not running macOS. The downside, is you have to be playing the Keynote at the same time the other is viewing. From memory only, look in Preferences of Keynote. You would have the Keynote on iCloud and share the link to it.

As per Apples Support info you can Present to another even if they are running windows

Link https://support.apple.com/en-ca/guide/keynote/tan683ecab0f/10.1/mac/1.0

make these settings first:

• Inspector > Document > Document:

• in the Presentation Type dropdown menu, select Normal

to create the movie file, go to: File > Export > Movie