Here's a quick list of things to check to get approval to launch ads with Facebook:
On their FB Account
Make Sure 2FA is setup
On their FB Business Page
Map Is Correct
Address
Business Phone
Business Email
Website
Do they have at least 7 posts that are relatively recent? If not, have them take 5 mins per day for 7 days to post about their company
On their FB Ads Manager
Select Maximum Date View to see all of ad spend
Make sure a payment method is on file
Help them understand FB restrictions if they have a new or unused account
If new or unused, Only launch one ad for 30 days.
After 30 days, you can launch multiple offers and use the account normally assuming there aren't any issues or restrictions