Move a page and its subpages to another space

[Mouna Hammoudi]

I am trying to move a page and all its children to another space but I cannot see the move option within the following menu. Anyone knows how the move operation can be done? 

[Matt]

Likely due to the page restrictions applied to that page. You may not have the appropriate permissions to perform the move, only to view it. Work with a Space Admin to understand more.

Here's the official doc: Move and Reorder Pages | Confluence Data Center and Server 8.6 | Atlassian Documentation

And the menu you are referring to is the correct place to find "Move".