[Plugin: Events Manager] Where do I change Search Layout?

you can do that using the template files however with regards to the events list you can try using EM Formats/Layouts in the settings

https://wp-events-plugin.com/documentation/using-template-files/

since I can’t see it, chances are you need to add CSS to your theme stylesheet to modify either widths of your theme or the search form itself so it fits.

My theme is fine as exemplified on the single event page.
It’s just the search layout I cannot find where to change.
What CSS do I enter for: em-events-search to take it from the column it is currently to a row?

sorry – it’s em-events-form that I need inline

sorry again – single event page is full width

it depends on your site and theme, you’d have to use different CSS depending on your theme CSS