Just right click on a empty spot on the page and you will see at the bottom of the menu the share option. Then you pick how you want to share the page.

Firefox has another feature to email a link to the current page, but it's a little hard to access. Either:

(A) Activate the menu bar by tapping the Alt key or F10 key, then File > Email Link

(B) Add the Email Link toolbar button from the Customize tab: Customize Firefox controls, buttons and toolbars

Your first time, you may need to set up your email account/client. See: Change the program used to open email links.

thank you for the help