Provide examples for creating ADServicePrincipal with Credential and Certificate

issue: #9842

Author: msJinLei

src/Resources/Resources/ChangeLog.md

@@ -19,6 +19,7 @@
 -->
 ## Upcoming Release
 * Make -Scope optional in *-AzPolicyAssignment cmdlets with default to context subscription
+* Add examples of creating ADServicePrincipal with password and key credential
 
 ## Version 1.9.1
 * Fix an error in help document of `Remove-AzTag`.

src/Resources/Resources/help/New-AzADServicePrincipal.md

@@ -205,6 +205,39 @@ PS C:\> Get-AzADApplication -ObjectId 3ede3c26-b443-4e0b-9efc-b05e68338dc3 | New
 
 Gets the application with object id '3ede3c26-b443-4e0b-9efc-b05e68338dc3' and pipes that to the New-AzADServicePrincipal cmdlet to create a new AD service principal for that application.
 
+### Example 7 - Create a new AD service principal using DisplayName and password credential
+
+```
+PS C:\> $credentials = New-Object -TypeName Microsoft.Azure.Commands.ActiveDirectory.PSADPasswordCredential -Property @{ StartDate=Get-Date; EndDate=Get-Date -Year 2024; Password="StrongPassworld!23"}
+PS C:\> $sp = New-AzAdServicePrincipal -DisplayName ServicePrincipalName -PasswordCredential $credentials
+
+ServicePrincipalNames : {exxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxc, http://ServicePrincipalName}
+ApplicationId         : exxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxcc
+ObjectType            : ServicePrincipal
+DisplayName           : ServicePrincipalName
+Id                    : 6xxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxb
+Type                  :
+```
+
+Creates a new application with name "ServicePrincipalName" and password "StrongPassworld!23" and creates the service principal based on the application just created. The start date and end date are added to password credential.
+
+
+### Example 8 - Create a new AD service principal using DisplayName and plain key credential
+
+```
+PS C:\> $cert = <public certificate as base64-encoded string>
+PS C:\> $sp = New-AzADServicePrincipal -DisplayName ServicePrincipalName -CertValue $cert  -EndDate "2021-01-01"
+
+ServicePrincipalNames : {cxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxx6, http://ServicePrincipalName}
+ApplicationId         : cxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxx6
+ObjectType            : ServicePrincipal
+DisplayName           : ServicePrincipalName
+Id                    : cxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxc
+Type                  :
+```
+
+Creates a new application with name "ServicePrincipalName" and certifcate "$cert" and creates the service principal based on the application just created. The end date is added to key credential.
+
 ## PARAMETERS
 
 ### -ApplicationId