"Which version of Zoho am I using" usually refers to which data centre region your account is hosted in, since this affects everything from your login URL to your API endpoints and which support and status pages apply to you.
The domain you use to sign in tells you your data centre directly:
| You Sign In At | Your Data Centre |
|---|---|
| zoho.com | United States |
| zoho.eu | European Union |
| zoho.in | India |
| zoho.com.au | Australia |
| zoho.jp | Japan |
| zoho.com.cn | China |
If the domain alone isn't conclusive, most Zoho products also show your data centre or account region in your organisation or company profile settings, typically under Settings, then Company Details, or a similarly named section, depending on the specific product.