To transfer tokens between accounts open the Keplr extension and click "Send":

Next, select the asset you want to transfer. Note, that Keplr will only show native and IBC tokens, but not ZRC-20 or ERC-20. Select ZETA from the list:

Enter the recipient address in the bech32 format (zeta***) and the amount you want to transfer. Please, note that the amount in Keplr is speficied in ZETA, so in this example you're sending 1 ZETA or 10¹⁸ azeta. You can also add a memo. Memo is optional and is often used when sending tokens to centralized exchanges.

Click "Next" to review the transaction details:

Review the transaction details and click "Approve" to sign and broadcast the transaction: