How do I forward emails from one sender to someone else in Gmail?

In Gmail settings, click on the FILTERS tab and see how you can narrow it down to the ones you want to forward.

Specifically you can filter on from / to / and words in the subject or body of the message.

Sorry @elbanditoroso but I already explained that I got to the filter stage but have a problem adding the email address that I want to forward to

Very cool. Thanks for teaching me something new, I had no idea those filters even existed.

I have a second e-mail account (“Account B”), so I just added that as a forwarding address. Account B received the request for confirmation which you mentioned. I confirmed, and was then able to tick the formerly greyed-out box in account A. I told Gmail to filter and forward anything with “Brownbear” as subject, and added that anything containing the word “Anti” should not be forwarded.

Account B did not receive any old messages, or any incoming messages without the subject “Brownbear”. It did receive messages titled, “Brownbear” and “Brownbear on vacation”, but did not receive the message I titled with “Brownbear” but added the word “Anti” to. So, it works as advertised, and will come in very handy for me.

Have you tried setting the “new” person up in your address book, before going to the filters.