This is the 324th most frequent Russian word.
заявление
"Zаявление" - a statement, application, or declaration.
In this sentence, the word "заявление" refers to an "application" or "request" submitted officially.
Он подал заявление на участие в конкурсе.
He submitted an application to participate in the contest.
Here, "заявление" means a "statement" or "claim" made or presented.
Её заявление о повышении вызвало недоумение у коллег.
Her statement about a promotion caused confusion among colleagues.
In this context, "заявление" signifies a "report" or "documented complaint" regarding an issue.