The indirect advertising does not directly advertise the product. Sponsorship is example of indirect ad.
The goal of the bandwagon ad is to convince individual consumers that a product is worth purchasing.
Endorsement uses famous person for the advertisement of the product.
Promotional ad includes special offers, cents off coupons, temporary price reductions ...
Endorsement is the technique of advertising that shows that multiple consumers use a product to build consumer trust in the product.