I'm trying to sign a bitcoin address but I cannot find the one that I actually have a balance in.
You can't sign message with your blockchain.info wallet addresses and you can't even know all of your wallet addresses there. You have to import bitcoin address into your wallet from which you can sign a message. And you can also see all your wallet addresses just like Yuuto said. I logged in my older Blockchain wallet and could see all my old addresses just by doing what the Blockchain support article says. https://support.blockchain.com/hc/en-us/articles/207746403-Addresses
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Manage
Your wallet automatically manages your bitcoin addresses for you by generating a new one each time you need one to receive a payment. You can click on Manage to the right of a category to see all of the individual addresses that have been generated for that specific category.
Your wallet automatically manages your bitcoin addresses for you by generating a new one each time you need one to receive a payment. You can click on Manage to the right of a category to see all of the individual addresses that have been generated for that specific category.
OP, you could also get your wallet xPub and see in the blockchain which address has the amount of Bitcoin you are talking about.
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Within the Manage section is a More Options button. You can edit the name of the category, make the category the default for receiving and sending, or archive it so it no longer appears in your balance (note that archived categories can be unarchived).
