There are three roles in the clan:

Regular Clan Member can:

Use the Clan Chat;
Send their Operators on Clan Missions;
Recall Operators from the mission before the timer runs out;
Get personal rewards for completing missions;
Add clan members to Squads (even if they are not on the Friends list);
Send out clan invitations to other players (Open Clans only);
Invest in the Clan Expansion and buy Clan Doublers.

Vice President (VP) can:

Do everything mentioned above;
Send out invitations if the clan is Private;
Delete Regular Members from the clan;
Change clan introductory message and the minimum rating for potential clan candidates (if it is an Open Clan).

President can:

Do everything mentioned above;
Delete Vice Presidents from the clan;
Change all clan Settings;
Assign the Vice President role to Regular Members and remove it.

NOTE: When the President leaves the clan, the position is transferred to the VP automatically. If there is more than one VP, the President's position will be given to one of the VPs randomly. If there are no VPs, one of the Regular Members will inherit the role.

NOTE: Be careful! After the President has transferred their role, it can only be transferred back by the new President. These changes are irreversible, neither automatically nor by the developers.