This is the 6048th most frequent Russian word.
сообщать
"Сообщать" means "to inform" or "to report."
Here, 'сообщил' is the past tense of 'сообщать', used to convey the act of informing someone about a specific piece of information.
Он сообщил нам важную новость.
He informed us about an important news.
In this sentence, 'сообщите' is used in the imperative form, addressing the action of informing in case questions arise, showing a request for communication.
Пожалуйста, сообщите, если у вас возникнут вопросы.
Please inform us if you have any questions.
Here, 'сообщают' is the present tense plural form of 'сообщать', indicating a habitual action of reporting or communicating data.