Microsoft 10 to Microsoft 7

Hi

I recently purchase Dell Inspiron 7000 and got Windows 10 with it.

However I would like to install Windows 7 OEM as I use the computer everyday for work and it is simply the Windows version of my preference. Thus I have 2 questions:

1. Can Dell provide me with a Windows 7 version or the ISO for it?

or 2. If not, can you please tell would it affect my warranty if I purchase it myself?

Best

Tamara