I keep opening the developer console of my browser, while visiting pages hosted via Adobe Experience Manager, anticipating that I should find the mcvisid stored in the session's cookies but I'm not finding it? I've been told it is stored in the "Adobe cookie", but not seeing any parent adobe cookie that would contain this value either.
Hoping that this isn't something calculated post-visit as part of Adobe Analytics, because the use case we have would need that value appended to a Marketo form as a hidden field when visitors submit while on the site.
I briefly tried to find "mcvisid" but had no luck -- I then reviewed my own cookies and saw AMCVS related cookies -- found document  which is the 'Experience Cloud Cookies' -- I verified on my own local AEM instance (localhost:4502) cookies and observed the related AMCV Name value pairs
Please check the document and see if these are the items that may help with your Marketo form requirements