1. SSH and login to ESXi 6.5
2. Go to VMware's website to download the patch (https://customerconnect.vmware.com/en/downloads)
3. login to the ESXi host, Upload the patch to ESXi datastore. Find the folder vmfs > volumes > Local-50 > upload the package to this folder or directly drag it into the folder
4. Type the credentials to log into ESXi host > type vmware -v to verify the version of ESXi
check the build number and version: https://kb.vmware.com/s/article/2143832
5. Put the server into maintenance mode: esxcli system maintenanceMode set -e true
6. Check maintenance mode: esxcli system maintenanceMode get
7. Check update patch: use cd command to open the folder where the update patch is stored
/vmfs/volumes/datastore1/esxi_update_65