Equation editor - where is it?

Equation editor - where is it?

How do I invoke the Equation Editor? I can't find a button for it on the toolbar, and nor is it anywhere obvious on the Insert menu. I am sure there used to be one, because here I am a year ago posting a bug report for it! https://help.zoho.com/portal/en/community/topic/problem-equation-editor-opens-inaccessibly.

Scratching my head!  Graham