To add or invite someone to your Squad you must be an admin or creator of the Squad. Then, click on the add people icon at the top right of the webpage near the chat icon.
To invite by link:
There's two ways to invite others, on 'Link' after clicking the Invite people pop-up, a custom link to the app and your Squad will be created, anyone with this link can join SquadPod, and join your Squad. Share it via social media, text, or even email.
To invite by email, enter the person you'd like to add email, and a default display name will be created, you or the invited user can change their display name later.
Check out Managing Roles and Permissions to read more about each role in squads, pods, and group chats.