The passive voice of ''apply''

Can this sentence "I have applied for samples that you requested." be replaced by this sentence"Samples that you requested have been applied"?

As far as I know, when the word "apply" means "ask", its part of speech is intransitive.But I have seen some sentences that use "apply" as passive voice. So it's quite confusing to me.

I believe your confusion is that the verb applied is indeed intransitive, but this is a phrasal verb that is actually being used here. This is indeed correct below.

Samples that you requested have been applied FOR.

What is happening is that this is the phrasal verb-

Apply for

Not

Apply

Please refer to this entry in the Free Dictionary about this phrasal verb.

A preposition at the end of a sentence in this example is correct because for is a particle of the verb phrase...