System.Convert.ToDateTime

PowerShell examples

[System.Convert]::ToDateTime('14:15'           )  # Today @ 14:15
[System.Convert]::ToDateTime('14:15:16'        )  # Today @ 16 seconds past 14:15
[System.Convert]::ToDateTime('2021-03-19'      )  # Specify a date
[System.Convert]::ToDateTime('2021-03-19 14:15')  # Date and time

See also