Signing a transaction is the final step of any transaction, like sending funds out of your account. A transaction will not be broadcasted in the blockchain until you sign it. You sign a transaction with your private key for your account, proving that you own this account. The signing process, however, depends on what wallet or account manager you use.

Signing a transaction on Polkadot-JS UI

NOTEFor most users, we strongly recommend using the Polkadot browser extension with Polkadot-JS UI to have better security and convenience. You can restore your existing account in the extension.

1. If your account was added directly on Polkadot-JS UI, you can sign a transaction in the UI. This is what you see after clicking "Make Transfer":

2. Here you can check the transaction details once again:
How can I verify what extrinsic I'm signing?

NOTE: in the transaction details, the amount is displayed in Planck. One DOT contains 10,000,000,000 Planck. You can read more about it in our article.

3. To sign the transaction, enter your account password in the "unlock account with password" field:

Then click the "Sign the transaction" button.

4. If you want to send other transactions soon, you can click on the "unlock for 15 min" slider. It will allow you to skip entering your password for the next 15 minutes.

5. Congratulations, you have signed a transaction! It will be included in the blockchain within a few seconds. You can now open any of the block explorers to view your transaction:

Cannot sign a transaction?

My password is invalid

We have compiled a few things to try in this article:
My password is not working!

If you don't know your password but have your mnemonic phrase, you can restore your account and set a new password.

My transaction failed

Signing a transaction means that it will be included in the blockchain. However, it doesn't always mean it will be executed. You can check the result of your transaction on a block explorer. Sometimes a transaction cannot be executed, and it fails:

Please check this article to help you understand why your transaction failed, fix the issue, and send the transaction again.