How do I permanently flag an e-mail as spam?

[Britanica]

I want to manually do it. I accidentally deleted the e-mail I had in my inbox. I want to manually add it to my spam/junk section.
Is there a way to do this manually and are there limits on how many people/places you can actually block?

[Chris]

You can block as many people as you like in Outlook. And you can definitely manually transfer email to your spam folder for sure.