In a Crowdfunding keyword, the Social Media buttons share the fundraising page you are currently viewing. In a Text to Donate/Event/Ticketing keyword & form, the Social Media buttons are on the Thank You page, after you've donated or bought tickets, to share the form to their friends and family.
Best Practice:Write your share messages from the perspective of the supporter or donor by using first person pronouns like "I" and "My". Remember that the volunteer fundraisers and donors will be the ones sharing, so write it as if they did it themselves. This will easily provide your volunteers with marketing material to use in their fundraising efforts.
Note: The Facebook title for social sharing with Crowdfunding and Peer-to-Peer Fundraising uses your organization's name as listed in MobileCause. Facebook share links with other activities, such as Text to Donate, Ticketing, etc. will use the Campaign Name as the Facebook share title.