When creating an ad, how does greg know what it will look like to his potential customers?

Description, a preview of the mobile and desktop version of his ad will appear when Greg will type his URL

The Correct Answer is: As Greg will type in his URL, headline, and description, a preview of the mobile along with the desktop versions of his ad will appear. 

• When Greg will type in his URL, headline, and description, a preview of the mobile and desktop versions of his ad will appear.
• Google provides various samples of desktop ads with the help of keywords selected in the campaign to create a generic preview.
• He must type in the specific keywords Greg is targeting once the ad has been approved, then view it in a browser 
• Previews of all the ads can be seen by logging into Google My Business account and choosing the Preview tab