What kind of machine can I use to install Linux Ubuntu? [closed]

There should not be any problem installing Ubuntu on most Win10 PCs, regardless whether you want to keep Win10 or erase the disk and install Ubuntu. Ubuntu's shim bootloader is signed by Microsoft (same as various other Linux distros), so you won't even have to disable Secure Boot. Installing and running Linux have never been easier!

As a rule of thumb, as long as you're buying from an established PC brand (HP, Lenovo, Dell, Asus, Acer, etc), everything should work. Don't buy Microsoft Surface laptops. They have various hardware (WiFi, webcam, touchscreen etc.) that isn't well supported. I suggest you choose a model you like and then search the Web for people sharing their experience of running Linux on it.