Yes. The exact combination of the recovery seed and the passphrase that you set are required in order to successfully restore the wallet and its addresses. The seed without the passphrase/with a different passphrase (as ABC Bits mentioned) will result in a different wallet being restored.
If you carefully and securely store the seed and your set passphrase, you should be able to restore it at any time in the future.
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So, you created a wallet with a mnemonic passphrase without really knowing how it works (or vague understanding)?
There is nothing wrong with giving things a try and learning through experience before going into something seriously. I think if that OP gave it a try/dry run (with no/very little bitcoin involved) then came here to ask a question, there is nothing wrong with that.