1. Sign in to Outlook Web App. For help, see Getting started in Outlook Web App.

2. At the top of the page, select Settings > Mail.

3. Under Options, select Block or allow.

4. To add an entry to Safe senders and recipients, enter the email address or domain that you want to mark as safe in the Enter a sender or domain here text box, and then press Enter or select the Add icon + next to the text box.

• For example, to mark all email from addresses that end in contoso.com as safe, enter contoso.com in the text box.
• To mark a specific person as safe, enter that person’s full email address. For example, to mark all messages from KatieJ@contoso.com as safe, enter KatieJ@contoso.com in the text box.

5. (Optional) Select the Trust email from my contacts check box to treat email from any address in your contacts folders as safe.

6. Select Save to save your changes.

To add a Safe Sender within your Gmail account, you will need to add a filter to notify the system to allow particular email type or senders to flow through to your inbox.

How to create a filter in Gmail:

1. Open Gmail.
2. In the search box at the top, click the Down arrow 
3. Enter your search criteria. If you want to check that your search worked correctly, see what emails show up by clicking Search. 
4. At the bottom of the search window, click Create filter. 
5. Choose what you’d like the filter to do.
6. Click Create filter.

Note: When you create a filter to forward messages, only new messages will be affected. ​Additionally, when someone replies to a message you’ve filtered, the reply will only be filtered if it meets the same search criteria. 

How to use a particular message you receive to create a filter:

1. Open Gmail.
2. Check the checkbox next to the email you want. 
3. Click More 
4. Click Filter messages like these.
5. Enter your filter criteria.
6. Click Create filter.

Adding contacts to your trusted Yahoo sender list is fairly simple as your Contact List is simultaneously your Yahoo email safe sender list.

1. Open the email sent to you by the contact you wish to label as safe. Be sure to check both the inbox folder and junk or spam folder.

2. Copy the email address

3. Click the Contacts icon located in the upper right-hand corner of your Yahoo! Mail Inbox Homepage. When you scroll over the first icon, it should say ‘Contacts’.

4. Click ‘Add a new contact’ located below the list of your contacts.

5.  Fill in the contact details and paste the email address you wish to add to your contact list.

6.  Click Save.