Microsoft Exchange (Outlook) and Gmail Spam filtering functions are used to manage email spam. All emailed spam will be sent to the junk folder in Exchange or the spam folder in Gmail. You can define blocked and Safe (allowed) senders using the tools available in your email account.
If you use any other application to read your email (e.g. Outlook Desktop App for Mac, Apple Mail, Thunderbird, Android mail apps) we recommend that you use Outlook on the Web to manage your Blocked and Safe senders lists to ensure that the rules you define are saved in your Exchange account.
If you would rather that emails identified as spam be delivered to your inbox, submit a request using the Opt out of Exchange Online Protection request form
You can use an existing message to block a sender in GMail
You can create a filter (“Never send it to Spam”) to stop any messages from going to the spam folder.