You can provide something to someone.* And you can provide someone with something.† You can even provide someone something.‡
And you can do all that in the passive voice as well, as you have demonstrated with your examples.
First let's look at the possible active voice versions of your message:
We provided a code to you. Enter the code that we provided to you.
We provided you with a code. Enter the code that we provided you with.
We provided you a code. Enter the code that we provided you.
Now let's make those passive:
A code was provided to you [by us]. Enter the code that was provided to you [by us].
You were provided with a code [by us]. Enter the code that you were provided with [by us].
You were provided a code [by us]. Enter the code that you were provided [by us].
Finally let's shorten those back up:
Enter code provided. (or Enter provided code.)
Enter code you were provided with. (It's really completely legal to end a sentence with a preposition, but if you meet resistance . . .
Enter the code with which you were provided.)
Enter code you were provided.
Take your pick. (I'd go with Enter provided code.)
provide, v.
* ‡ 6. transitive. To supply (something) for use; to make
available; to yield, afford. Frequently with for, to, indicating
the beneficiary. Also occasionally with indirect object without to.
1899 W. BESANT Orange Girl ii. xxvi. 431: The contractors..do
honestly provide the convicts the rations prescribed by the
Government.
1942 LD. ALANBROOKE Diary 26 May in War Diaries (2001) 260:
He is trying to stop deliveries of aircraft to us in order to provide
sufficient aircraft to USA pilots!
† 10. transitive. To supply (a person, animal, place, etc.) with
something. Frequently in passive. b. With with.
1913 C. GRAHAME-WHITE Aviation 214: The pilot and his
passenger are provided with a completely covered body, which they
enter through a small door.
1990 S. FRASER in M. Kurc That reminds Me xi. 45: Since we
were all so famous, no one had provided us with namecards.
Source: Oxford English Dictionary (login
required)
provide something [ to somebody] provide somebody with something //// So, a code was provided to you ... and you were provided with a code. The licensed variants of your sentence are correspondingly Enter the code that was provided to you and Enter the code that you were provided with. //// 'Provide' hasn't yet made it into ditransitive territory *provide somebody something.
– Edwin Ashworth May 26 '20 at 19:02Enter the code that you were provided with.is completely fine despite ending with "with"? – ispiro May 26 '20 at 19:07