To download the VMware vSphere Client 6.7 (often referred to as the HTML5-based client or the legacy C# client depending on the specific version), you generally need an active Broadcom/VMware account with valid entitlements.
Similarly, this is built into the ESXi 6.7 host and accessed via vmware vsphere client 6.7 download free
Since Broadcom's acquisition of VMware, the download process has moved to the Broadcom Support Portal 1. Where to Download To download the VMware vSphere Client 6
The official and safest way to acquire VMware software is through the Broadcom Support Portal vSphere Client (HTML5): vmware vsphere client 6.7 download free
For version 6.7, the "client" is built into the vCenter Server Appliance (vCSA). You don't download it separately; you access it via a web browser directed at your vCenter IP. ESXi Host Client: