how can i add a keyboard to my apple watch

If you want the native keyboard on Apple Watch, you need a newer watch. But this app in the App Store will work on a Series 5 watch as long as you own an iPhone which is updated to iOS 13 or higher --> https://apps.apple.com/us/app/flicktype-keyboard/id1359485719

Hi nnikolee,

We can understand wanting to use a keyboard on your Apple Watch when sending messages. The QWERTY or QuickPath keyboard is only available on the Apple Watch series 7 and Apple Watch series 8 and is not available in all languages.

Use the QWERTY and QuickPath keyboard: (Not available in all languages, Apple Watch Series 7 and Apple Watch Series 8 only) 

Check out: Send messages from Apple Watch

Have a good one!