Follow the instructions below to create an Outlook signature from a batch file and force the change in the registry.

Here are the commands to create the key. Enter the signature name in Outlook as the value

reg add HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\MailSettings /v NewSignature /t REG_EXPAND_SZ /d SigName /f
reg add HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\MailSettings /v ReplySignature /t REG_EXPAND_SZ /d SigName /f

References:
https://stackoverflow.com/questions/433493/why-does-html-require-that-multiple-spaces-show-up-as-a-single-space-in-the-brow

https://www.w3.org/TR/CSS21/text.html#white-space-prop

https://www.experts-exchange.com/questions/28525021/How-to-Query-Active-Directory-for-specific-attribute.html

https://social.technet.microsoft.com/Forums/ie/en-US/f9fd782e-ecdb-41e1-b00a-0b4b2cfd7d32/outlook-signature-registry-settings

https://www.codetwo.com/kb/gasmo-profile/

https://superuser.com/questions/251794/how-can-i-specify-reg-expand-sz-entries-in-a-reg-file

https://www.lifewire.com/net-user-command-2618097

https://community.spiceworks.com/topic/949313-what-is-the-windows-variable-for-a-users-full-name-not-just-the-username

https://stackoverflow.com/questions/9318614/bat-file-to-create-a-complex-string-variable-with-special-characters