There are several ways you can share a post. You can share it with one of your contacts or through a specific app.
The first way to share a post is to click on the button named "share" found at the bottom right-hand corner. There all the options for sharing will be displayed (share it as a text or through an app of your choice).
The second way is to click the three dots located at the top right-hand corner of the post. Click on "share post," and the same options as the ones previously stated will appear.