My friend wants to sell me a 2015 Ford Fiesta with 100,000 miles on it for $7000. What do you think about this? It has no known issues. I’ve never owned a Ford Fiesta.
My friend
2015 Ford Fiesta with 100,000 miles on it for $7000
What do you think about this?

If it's an automatic, run like the wind away from that car. The Focus and Fiesta had the same PowerShift dual clutch transmission, which Ford faced a class action because they were knowingly making bad transmissions.
I agree with the above comments. If is is an automatic transmission, your friend wants to get rid of the car and your friendship simultaneously.
Only if it has a manual transmission and a good mechanic gives it a clean bill of health - and you can get it for about half that price. If it has an automatic transmission your "friend" is likely looking to dump it wherever he can.
https://www.caranddriver.com/news/a30689585/ford-settlement-transmission-lawsuit/