How can I filter emails from the same senders? How can I mark an email that needs to be answered and get daily alerts until it is answered?

How can I filter emails from the same senders? How can I mark an email that needs to be answered and get daily alerts until it is answered?

You can create filters based on the From addresses of the senders. Read more about it here. To get alerts for regular followups with your leads and contacts, you can either create a recurring task to get daily reminders to reply to an email, or setup a reminder in the email itself.