In Colorado, where I practice law, the person who signs the incorporation papers, generally speaking electronically, who is called "the incorporator" has full discretion to do anything consistent with the articles of incorporation until directors are appointed (at which point the powers of the incorporator are spent), and there would usually be a brief period between incorporation and the appointment of directors, followed by another brief period between the appointment of directors and the appointment of officers and issuance of shares. Your mileage may vary as state laws on these nuts and bolts details differ somewhat. The relevant statue in Colorado reads as follows:
Colorado Revised Statutes § 7-102-105. Organization of corporation
(1) After incorporation:
(a) If initial directors are not elected in the articles of
incorporation, the incorporators may hold a meeting, at the call of a
majority of the incorporators, to adopt initial bylaws, if desired,
and to elect a board of directors; and
(b) The initial directors may hold a meeting, at the call of a
majority of the directors, to adopt bylaws, if desired, to appoint
officers, and to carry on any other business.
(2) Action required or permitted by articles 101 to 117 of this title
to be taken by incorporators at an organizational meeting may be taken
without a meeting if the action is taken in the manner provided in
section 7-108-202 for action by directors without a meeting.
(3) An organizational meeting may be held in or out of this state.
Once a corporation has directors, those directors can appoint officers to act on behalf of the company, and can issue shares on such terms as they see fit. A corporation can generally only take binding legal action through its officers, so until directors have been appointed and in turn appointed officers of the corporation, it basically can't do anything.
But, this is generally not a great concern because until there are shareholders, there is generally no property in the corporation because no one has made any contributions to capital.
In the case of a non-profit, by the way, in Colorado at least, the default in a case of defective incorporation is not a general partnership, but an unincorporated non-profit association.
Importantly, non-profit corporations rarely have shareholders and for profit corporations can exist without shareholders so long as they have directors and officers, even though they rarely do. Tax law, for example, does not require a corporation taxed as a C corporation rather than as an S corporation, to have shareholders.