How to create bulk email distribution groups?

To create bulk distribution groups at one time, and add multiple members to each distribution group, please take to the following steps:
1. Install and configure Windows PowerShell.
2. Connect Windows PowerShell to Exchange Online.
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Create bulk distribution groups at one time
1. Prepare a CSV file to import multiple distribution groups, and store it in local disk (for example, C:\distributiongroups.csv ).

For example:
Name, Type
Group1, Distribution
Group2, Distribution

Note:
Name represents display name of the distribution group.

2. Run the command below to bulk import several distribution groups:
Import-CSV "D:\distributiongroup.csv" | foreach {New-DistributionGroup -Name $_.name -Type $_.Type}
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Add multiple members to each distribution group
1.Prepare a CSV file to contain each user's information, including Display name, Alias, E-mail address, and then store it in local disk (for example, D:\list.csv ).

For example:
Display name, Alias, E-mail address
Member1, member1, member1@contoso.com
Member2, member2, member2@contoso.com

2. Import the CSV file to Exchange Online via PowerShell.
Run the cmdlet:
Import-Csv "D:\list.csv" | foreach{Add-DistributionGroupMember -Identity "GroupName" -Member $_.alias}
Note:
GroupName represents the distribution group needs to be added members.
 

After those steps, you can create multiple distribution groups at one time, and add several users into them.

Merge items from multiple calendars

Merging the calendar information is a two-step process. First, items from one calendar are exported. Second, the exported calendar information is imported so that it is merged with the calendar where you want all calendar items to appear.

Export calendar information

1. Click the File tab.
2. Click Options.
3. Click Advanced.
4. Under Export, click Export.
5. Click Export to a file, and then click Next.
6. Click Outlook Data File (.pst), and then click Next.
7. Click the calendar folder that you want to export, clear the Include subfolders check box, and then click Next.
8. In the Save exported file as box, enter a folder location and file name, or click Browse to select a folder and enter the file name.
9. Click Finish.

 NOTE    Exporting calendar items makes a copy of the items, but does not delete the items from any calendar.

Import calendar information

1. Click the File tab.
2. Click Open.
3. Click Import.
4. Click Import from another program or file, and then click Next.
5. Click Outlook Data File (.pst), and then click Next.
6. Click Browse to select the file you created in the previous section, and then click OK.
7. Under Options, click Do not import duplicate items, and then click Next.
8. Under Select the folder to import from, click the Calendar folder.
9. Clear the Include Subfolders check box.
10. Click Import items into the same folder. If you have multiple accounts, you might have different Outlook Data Files. Click the destination account where you want the calendar items to appear.
11. Click Finish.