Can send emails or not

Hi I want to know that can I send emails from infinity domain with free plan.

If you mean manually sending emails by using .epizy or .rf.gd domains then of course you can… However there is pretty slight chance that some other e-mail clients and servers could mark your e-mail as spam due to the free/uncommon subdomain…

There is an entire knowledge base category about e-mail related things: https://infinityfree.net/support/email