AWS KMS Encryption enable for SQL Server Columns?

We can't download the KMS key for custom master key creation , We need to use the kms encryption key with application code

As per sql server blog here On SQL Server side, it is supported to use a custom key store provider for Always Encrypted, but the implementation/support of the custom key store provider comes from the service provider itself, which in this case is the AWS KMS.

For further your ref here