Dizer is an irregular verb.
It can have different meanings (to say, to tell, to speak) depending on context.
The third person singular (ele/ela = he/she/it) is used a lot in newspapers.
Ele/Ela diz/disse que … He/She/It says/said that …
Exemplo: COI diz que 80% dos ingressos dos Jogos Olímpicos já estão vendidos.
Example: IOC says that 80% of the Olympic Games tickets are already sold.
COI (Comitê Olímpico Internacional) = IOC (International Olympic Committee)