There is an official ARM Template for creating a Key Vault and a list of multiple secrets: https://github.com/Azure/azure-quickstart-templates/tree/master/quickstarts/microsoft.keyvault/key-vault-secret-create
There are some existing examples online using for loops in bash combined with Azure CLI, like this one and this one.
There aren't too many "official" examples apart from the ARM one I shared, but there are a lot of custom solutions shared online.
Azure CLI command reference: https://learn.microsoft.com/en-us/cli/azure/keyvault/secret?view=azure-cli-latest
PowerShell: https://learn.microsoft.com/en-us/azure/key-vault/secrets/quick-create-powershell
Let me know if this helps and if you have further questions.
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