U.S. Constitution, Twenty-Fifth Amendment, Section 2
Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress.
Notes
Requires the President to nominate a Vice President whenever there is a vacancy in that office. Sets the nominee to take office upon confirmation by a majority vote of both houses of Congress, so filling the vacancy needs approval from the House and the Senate.
Use as reference
Lexinter.net | U.S. Const. amend. XXV, § 2 | https://laws.lexinter.net/constitution/us/amendment-25/section-2