How to install it
Gmail: Settings (gear icon) > See all settings > General > Signature > Create new > paste > click Save changes at the bottom.
Outlook (web / new): Settings > Account > Signatures > paste > Save, and select it as the default for new messages and replies.
Outlook (classic, Windows): File > Options > Mail > Signatures > New > paste > OK.
Apple Mail: first paste it into a new email, copy it again, then paste it under Settings > Signatures.