Linkedin text ad is closest to other search engine ads you can get on this platform. They operate on the principle of ppc & we recommend to use them for driving traffic to websites or landing pages and attracting job candidates.
These kinds of ads are boosted from the company's own feed. They look and feel native to the platform itself. We recommend using them for generating leads, increasing awareness & boosting engagement.
You might have come across a chain of mails that are sitting in your inMail. These are ads, which can be sent by curating a target list with a CTA button and after A/B testing. We recommend using it for generating B2B leads.
Like any other advertising platform, LinkedIn also, provides feature of setting a budget and bidding to optimise an ad. Also all campaigns can be measured in terms of conversions, number of leads and engagement.