Hi VillarrealAndreaL,
You can use the option docstring when creating or altering a table, for example:
.create table Telemetry (DeviceID: string, Timestamp: datetime, WaterTemperature: decimal, AirHumidity: decimal) with (docstring = "Table description")
More information: https://learn.microsoft.com/en-us/azure/data-explorer/kusto/management/alter-table-docstring-command