Below their username and stats, you will see their permissions. Keep in mind that in mind that you need at least ten active players in your clan to declare war.
[header] How to do clan wars on clash of clans [title] Start a clan war. [step] If you're just a member of clan, ask in your clan chat for a leader or co-leader to start a clan war. [substeps] If you don't know any staff in your clan, click on view clan and browse through a list of your clanmates.