undercover police officers identify themselves when making an arrest.

>Governing Laws on Officer Identification

>The requirement for police officers to provide their name and badge number varies across the United States. While no federal law mandates disclosure, many states and municipalities have their own statutes aimed at enhancing transparency and accountability. These laws often require officers to identify themselves during specific interactions, such as traffic stops or arrests, to ensure citizens can hold law enforcement accountable.

https://legalclarity.org/does-a-police-officer-have-to-give-...

ICE where uniforms that say "ICE" in big letters. That's identification. Undercover police officers might identify themselves during an arrest, but only as "police." Undercover police officers aren't going to give you their name and badge number if you ask them.

>Situations Where Disclosure May Be Withheld

>While officers are generally expected to provide their name and badge number, there are situations where disclosure may justifiably be withheld. During undercover operations, revealing an officer’s identity could compromise safety and the operation’s integrity.

>In protests or crowd control situations, officers may face security concerns, such as risks of doxxing or harassment. To address this, some departments allow officers to withhold identification while still requiring visible markers, like badge numbers, to maintain accountability without endangering safety.

This stuff is trivially googlable.