If you would like to share your boards, you can invite individuals, create a team, or make the board public to be viewed by all.
To invite individuals select the Invite option at the top of the board. Type the name or email address of the person you want to invite. If the person already has a Trello account you can try to search by name. If you are unsure if the person already has a Trello account, you can send them an email. They will be prompted to sign up for a new free account if they aren't already registered.
To create a team, select the Personal link at the top and then select Create Team option. From here you can add members to your new team.
To change the visibility of a board, select the Private link at the top. From here you can set the board from private to public.