Find text in a message
You can search for specific text in the current message. If the message is part of a conversation, Mail searches the entire conversation.
Press Command-F, then type a word or phrase into the search field that appears across the top of the preview area.
Do any of the following:
Go to the next or previous instance in the results: Click the arrow buttons located beside the search field.
Clear the search field: Click the Clear button at the end of the search field.
Set options for the current search: Click the magnifying glass in the search field. You can ignore case, or search for text that contains or starts with the word or phrase you typed.
When you’re ready, click Done.