In the active form we give importance to the doer (originator) of the action/the person performing the action.
In the passive form the thing done is given importance to.
Often when we use the passive forms it is quite unnecessary, undesirable and difficult to mention the names or identities of the persons/ agents who perform the action.
Two passive forms are possible
Some sentences have a direct object and an indirect object. These sentences can have two passive forms.