Recognise is an alternate spelling of the same verb. It means the same thing and can be used in all the same contexts. Recognise is more common in British English than it is in American English. That said, even the British prefer recognize—and have for some time.

What do you mean by recognize?

: to know and remember (someone or something) because of previous knowledge or experience. : to accept or be aware that (something) is true or exists. : to accept and approve of (something) as having legal or official authority.

Is it Recognising or recognizing?

Recognize. --> American spelling, but accepted elsewhere. Recognise. --> British spelling, used throughout the Commonwealth, but frowned upon in the U.S.