Formal:
* Declare: To state officially or formally.
* Proclaim: To announce something publicly and officially.
* Publish: To make something known to the public.
* Disseminate: To spread information widely.
* Pronounce: To state something clearly and firmly.
Informal:
* Say: To speak or utter something.
* Tell: To inform someone about something.
* Break the news: To reveal something new or important.
* Let know: To inform someone about something.
* Share: To make something known to others.
Other:
* Broadcast: To transmit something by radio or television.
* Report: To give an account of something.
* Reveal: To make something known that was previously hidden.
* Signal: To indicate something by a sign or action.
The best synonym will depend on the specific context and the tone of your writing.