DateTime to LongDate 
Get-Date $date -Format D
Details
Format a DateTime value in the LongDate format

Example
PS C:\> $Date = Get-Date
>> Get-Date $date -Format D

Thursday, March 28, 2019
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DateTime to ISO8601 
$offset = ([System.TimeZoneInfo]::Local).BaseUtcOffset.ToString()
$offset = $offset.Substring(0,$offset.LastIndexOf(':'))
$date.ToString("yyyy-MM-ddTHH:mm:ss.fff") + $offset
Details
Format a DateTime value in the ISO8601 format

Example
PS C:\> $Date = Get-Date
>> $offset = ([System.TimeZoneInfo]::Local).BaseUtcOffset.ToString()
>> $offset = $offset.Substring(0,$offset.LastIndexOf(':'))
>> $date.ToString("yyyy-MM-ddTHH:mm:ss.fff") + $offset

2019-03-28T11:06:01.608-06:00
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DateTime to ISO8601UTC 
$date.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ss.fffZ")
Details
Format a DateTime value in the ISO8601UTC format

Example
PS C:\> $Date = Get-Date
>> $date.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ss.fffZ")

2019-03-28T16:06:00.050Z
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DateTime to SQL 
$date.ToString("yyyy-MM-dd HH:mm:ss.fff")
Details
Format a DateTime value in the SQL format

Example
PS C:\> $Date = Get-Date
>> $date.ToString("yyyy-MM-dd HH:mm:ss.fff")

2019-03-28 11:05:58.440
  |  
DateTime to RFC1123UTC 
Get-Date ($date.ToUniversalTime()) -Format r
Details
Format a DateTime value in the RF C1123UTC format

Example
PS C:\> $Date = Get-Date
>> Get-Date ($date.ToUniversalTime()) -Format r

Thu, 28 Mar 2019 16:05:56 GMT
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