‘Open’ is an adjective that means ‘not closed’.
They left the door wide open.
Is the shop open in the evening?
‘Opened’ is the past tense of the verb ‘open’.
She opened the door very fast.
Jim opened his eyes, and saw a big cake on the table.
We can say ‘is opened’ when it’s done by someone.
The shop is opened by the owner. (It’s similar to ‘The job is done by the manager’)
The supermarket is opened at 8 am by the manager.