Every record in a workflow is either a company or a person. Most steps work on one type, so the type flowing at each point decides which steps you can add next. This is why the builder greys some steps out.
Where the type comes from
The type is set by your sourcing step or your trigger:
Companies: Companies from segment, Company search, Company lookalikes, and the company event triggers (CRM: Deal closed, CRM: Deal created, CRM: Company created, Leads: Company added, Ocean: Companies sent) all start with companies.
People: People search, People lookalikes, and the people event triggers (CRM: Person created, Leads: Person added, Ocean: People sent) start with people.
Switching from companies to people
One step changes the type: Find people at company. It takes companies in and produces the people found at each. Everything after it works on people.
There's no step that turns people back into companies — plan the order so the switch happens where you need it.
Which steps accept which
Company steps: Segment fit, Crawl website, Send companies to CRM, Save companies to leads. (Companies from segment, Company search, and Company lookalikes produce companies.)
People steps: Enrich email and phone, Send people to CRM, Add to sequence, Save people to leads. (People search, People lookalikes, and Find people at company produce people.)
Either type: AI research, Text, Google search, Compare websites, Route, Branch, Filter, Delay, Parse JSON, Summarize run, Notify, Generate CSV link, Add to spreadsheet, HTTP request.
Why a step is greyed out
If a step is greyed out in Add a step, it doesn't accept the type flowing at that point. For example, Enrich email and phone (people only) won't be offered in a company workflow until you've added a Find people at company step. The picker shows the reason on hover, and groups incompatible steps under an Incompatible header.