Hello,
I wanted to know that if I create a logo film that I need to play before our film is played in the theatre (Kind of like Universal, Paramount, Legendary etc), will we be able to use it for free? or how does that work? The movie will be shown in multiple countries. Sorry I am new here so I have no idea how this works. Thank you.
is free.
if you are not creating a game or app that includes the engine then all is free. in your case you are creating a video file so is free.
But check twice that the assets you will use in the video are licensed correctly, textures, 3D models, sounds.
Down this page. click on How much do I have to pay for Unreal Engine
Hey there @PtechPOS! Welcome to the community! Doru already mentioned most of what is relevant as always but just to add the EULA as I have to I’ll just drop this here. As long as you don’t include any engine source, it’s just the render, and follow the rest of the EULA, you’re good. There are still some more rules to go over. I recommend to take a long read of the EULA at the link below:
Thank you so much for the reply. That clears out a lot of things! Appreciate the help! 
I will definitely look into the EULA, and thank you for the clarifications and the answers. Much appreciated