To use Multi-Channel Funnels you must need to enable Goals or Ecommerce.
- Advertising features
- In-page Analytics
- Custom dimensions
- Goals or Ecommerce
The correct answer is: Goals or Ecommerce
In Analytics, conversions, goals, and eCommerce transactions are credited to the last campaign, search, or ad that referred the user when they converted. To use Multi-Channel Funnels, you must need to enable goals and eCommerce.
Analytics compiles conversion path data for any Goal or Ecommerce transaction you define. The Multi-Channel Funnels reports are generated from conversion paths, the sequences of interactions (i.e., clicks/referrals from channels) during the 90 days1 that led up to each conversion and transaction.
Read More: https://support.google.com/analytics/answer/1191182