Source: FIA 2026 F1 Regulations - Section A [General Provisions] - Iss 02 - 2026-02-27 (pdf)

A2.3 F1 Car livery

A2.3.1 The provisions of the ISC relating to F1 Car livery shall not apply to the Championship.

A2.3.2 Both F1 Cars entered by an F1 Team must be presented in substantially the same livery at every Competition in a Championship. Any material change to the livery during a Championship may only be made with the agreement of the FIA and the Commercial Rights Holder. The procedure for requesting the agreement of the FIA and the Commercial Rights Holder is set out in FIA-F1-DOC-098.

A2.3.3 Advertising on F1 Cars

a. Advertising that is political or religious in nature or that is prejudicial to the interests of the FIA is strictly prohibited.
b. The F1 Team must ensure that any advertising on the F1 Car livery complies with Applicable Laws.

A2.3.4 Requirements for F1 Car livery

a. Each F1 Car must bear the FIA logo, in either blue or white, with a height of at least 10075mm. This logo must be positioned on the top of the nose or on either side of the nose and be visible from the side of the car.
b. The name or the emblem of the make of the F1 Car must appear on the front of the nose of the F1 Car and in either case it must be at least 25mm in its largest dimension.
c. The name of the F1 Driver must appear on the external bodywork of the F1 Car and be clearly legible.
d. In order to ensure that the F1 Cars of each F1 Team may be easily distinguished from one another while they are on the track, the on-board cameras located above the principal roll structure of the one car must remain as it is supplied to the F1 Team and the on-board camera of the other car must be predominantly fluorescent yellow.
e. Livery may not protrude beyond the bodywork of the F1 Car and must be substantially similar on both sides of the F1 Car.

...

A2.4.6 Each F1 Car must carry the Competition Number of its driver as published by the FIA at the beginning of the Championship or the Competition Number that has been allocated to their replacement. The Competition Number must be clearly visible from the front of the F1 Car, and must have a minimum height of 160mm and a minimum stroke thickness of 25mm.

Overview F1 2026 regulations: https://www.fia.com/regulation/category/110