Thank you for the responses !
I just want an evaluate version.
I went to the link ' https://my.vmware.com/en/group/vmware/evalcenter?p=free-esxi7', then i registered and get access to the both download.
i downloaded : 'VMware vCenter Server Appliance', but after extract the iso 'VMware-VCSA-all-7.0.3-22357613', i cant find an iso to put on my usb key and install it on one of my computers.
I saw on some tutorial an iso called 'VMware-VMvisor-installer..... .iso'.People put that iso on usb key by rufus, then they can install it on a fresh computer.