Do I need permission to make an Ubuntu section in my computer store?

I have a computer repair shop and I offer Ubuntu as a good option for students.

I want to make a section on my store focused on Ubuntu, with at least 3 computers running Ubuntu for discovery, practice and advice.

I don’t know if I need some kind of permission to do this.

Please see: http://www.ubuntu.com/about/about-ubuntu/licensing

The licence of software included in Ubuntu can not discriminate against anyone or any group of users and cannot restrict users from using the software for a particular field of endeavour - a business for example.

You don't need any permission.

Software licensing of Ubuntu packages is one thing and poses no problems here. The other involves the intellectual property rights of Canonical, the company behind Ubuntu. I assume you might want to not only install Ubuntu on those computers, but also to put up some logos or advertising for it.

Then you are bound to the intellectual property policy of Canonical, which can be found under http://www.canonical.com/intellectual-property-policy. In addition, the Ubuntu logo usage guidelines under http://design.ubuntu.com/brand/ubuntu-logo might be of interest, with a download link at the bottom.