1. Use the [Download / export] button at the bottom left of the window and choose the "Read only HTML page..." option. This will create a file that can be viewed off line in a browser.
2. If the person you want to share with is on the tree, select him/her then click on the [Share] button (top right). To prevent them from editing, make sure the "Allow Xxxxx to edit family" is unchecked. Copy the link at the bottom of the left panel and email the link. Don't use the [Send Email] button as it is unreliable.