Xcode / Working for a completely distinct application but parallely to another one I used to work on my own mobile application through my Apple Id, tied to my own mail address.

Now, I am working for a company aiming to build their application.
In order to correctly put the application build on my iPhone device in development mode, must I completely use a different Apple Id, meaning tied to my mail inside the company? 

To put in a nutshell, how to work parallely for distinct companies with Xcode?    

Note: Using my own Macbook Pro device.
Correct me if i misunderstood your question. You want to work in a machine with different developer account. Yes you can.

Go to Xcode>Preferences>Accounts and sign in with as much developer id you want to use. Make sure that you have all the certificate, public key and privet key pair in your Mac Keychain. For details you can refer this link

Next time when you work on an app in Xcode please choose the team from target settings