Deekit app for iPhone and iPad

Deekit is a collaborative whiteboard, unlimited canvas where you and your team can draw, write, edit or add other content. Together, in real time.

Features:
– real-time collaboration
– supported content types for collaboration: drawing, short text, long text notes, images
– tools for adding and editing your content
– sharing your boards with others (your team, customers, anyone)
– see your team activity
– setting up your team and managing access
– your boards are automatically synced and stored, so you never need to worry about unsaved changes
– templates

See https://www.deekit.com/ for more.