When someone suggests something, they mention an idea or a plan for someone else to think about or do.
When someone suggests something, it is usually helpful or friendly because they are trying to give a good idea.
Examples:
She suggests going to the park for a picnic.
He suggests that we should read a book together.
I suggest we play a game.
The teacher suggests a fun project for the class.
My friend suggests we should have a party every day!
The sign suggests that we should walk, not run.