You are trying to use the Leads view in SAP Business ByDesign mobile application, how you do not find it.
SAP Business ByDesign
Currently it is only supported to use the Leads functionality in the mobile device if the With Handover scenario has been scoped.
The functionality has been added to our product backlog to be implemented in a future release
This is the current system behavior.
An alternative option may be to check the SAP Customer Influence Platform to submit an idea.
Leads, New Business, Marketing, With Handover, Without Handover, Mobile, Application , KBA , AP-LP , Lead Processing , Product Enhancement