Adding a button that enables you to share the content of your bot is really easy and can be used with any cards.
Using cards format, create a button "Share"
Select the type button : share this card
The button name is by default:
In english "Share"
In french "Partager"
If you need more languages please contact us.
If you want to push people to share your bot
Create a recipe with a card that presents your bot.
Add a first button with the link to your bot
Add a second button with a share button.
Then add a link to this recipe in your persistent menu (or anywhere else)