There are two ways to generate leads from LinkedIn
1. Organically: Post on LinkedIn from your company profile or business profile often. The organic reach of LinkedIn is quite high nowadays as compared to any other social network. The content you post should essentially take users to a blog or a resource that you have created which is gated. Also, get your employees to post on their LinkedIn profile. Make sure you build contacts on LinkedIn - You could have 30k first degree connections on LinkedIn. A quick way to get connected with others on LinkedIn in your domain is to export your email contact list and import it into LinkedIn. That way you could expand reach for most of your posts.
2. LinkedIn Ads: LinkedIn Ads work well for B2B businesses who want to target decision makers. I recommend that you use Sponsored Content to promote a post from a company page. Make sure you use the LinkedIn lead form that allows you to capture leads which can be exported to a spreadsheet. The lead form auto-populates all fields from the target audience profile, so there is very little friction while capturing data.