Once you've determined what kind of sponsor ID must be provided, here are the rules for how it must be communicated.
Print ads and websites
Display sponsor ID and any party preference in an area set apart from the ad text. Sponsor ID and party preference should be on the first page of a multiple-page ad. Use at least 10-point type; do not screen or half-tone the text. Exception: If a person contributes cash, goods or services to the campaign in order to assist in paying for an ad, it is not necessary to show this contributor's name as a sponsor. The candidate or the candidate's committee may be shown as the sponsor instead, provided the candidate properly reports the contribution.
Billboards and posters
Use type that is at least 10% of the largest size type used in the ad.
Small online ads with limited characters
Display sponsor ID in an automatic display such as a mouse tip/rollover or nonblockable pop-up that remains visible for at least 4 seconds OR on a webpage that is conspicuously linked to the small ad and reached with one mouse click.
Broadcast, video, and online audio ads
Clearly identify or speak the sponsor's name and any party preference. Sponsor's address is not required.
The Top 5 (and Top 3, if applicable) contributor information required in videos and television ads about ballot measures may be displayed on the screen for at least 4 seconds in letters greater than 4% of the visual screen height on a solid black background on the entire bottom one-third of the television or visual display screen or bottom one-fourth of the screen if the sponsor does not have or is otherwise not required to list its top five contributors, and have a reasonable color contrast with the background. Abbreviations may be used when naming a Top 5 contributor, if the full name of the contributor has already been clearly spoken in the advertisement.