What does collapse message mean?

Hey there SakivEdorak,

We understand you're asking about what the option to collapse a message will do. We'll be happy to help.

In the Mail app, when you collapse a message, it will hide or minimize a message or email. If you're referring specifically to the collapse read emails option, this will hide emails in a thread of emails that have already been read by you.

For instructions on how to adjust these options and a few more details, check this out: Search for and view email on your iPhone, iPad, or iPod touch

Let us know if you have any other questions. Cheers!