If you want to see because you are viewing an ad or want to check who your competitor is targeting with an advertisement, then you can use the following advice.
On the paid ad (marked with Sponsored), click the three points in the right upper corner. A popup menu will appear where you have the option Why am I seeing this? When you click this option, you will get information about the interest in targeting and / or demographic information.
TIP: If you want to see the advertisements of your competitors, like their FB page and frequently visit their website.